项目实战--Message Queue

一. 概念篇

我们在学习多线程的时候,学习过生产者-消费者模型,为了实现解耦合和削峰填谷,引入了阻塞队列.

在实际的后端开发中,跨主机之间使用生产者消费者模型,也是非常普遍的需求,因此,阻塞队列会被封装成一个独立的服务器程序,实现更丰富的功能.这样的程序称为"消息队列" .

市面上成熟的消息队列非常多,有Kafka,RabbitMQ,RocketMQ,ActiveMQ...接下来我们要实现的MQ就是以RabbitMQ为蓝图的.

在实现MQ之前,我们先来认识几个核心概念.

1.1 核心概念

1. 生产者(Producer) : 负责生产消息

2. 消费者(Consumer) : 负责消费消息

3. 中间人(Broker) :?消息队列

4. 发布(Publish) : 生产者生产消息并存放到消息队列中

5. 订阅(Subscribe) : 消费者预订某个Queue的消息,不是把消息从Broker中取出来,也不是消费消息

1.2 有关Broker的概念

1. 虚拟机(VirtualHost) :类似于MySQL中的database,是一个逻辑上的集合,一个Broker上可以存在多个虚拟机

2. 交换机(Exchange) : 生产者先把消息发送到Broker的Exchange上,再由Exchange根据不同的规则转发给不同的Queue

3. 队列(Queue) : 真正存储消息的实体,每个消费者决定自己从哪个Queue上读取消息

4. 绑定(Binding) : Exchange 和 Queue之间的关联关系.Exchange 和 Queue之间可以理解成"多对多"的关系,每对关系可以用一个Binding来表示.

5. 消息(Message) ; 传递的内容

1.3 交换机类型

刚才我们提到,Exchange和Queue之间是"多对多"的关系, 其实是由交换机的类型决定的.

以RabbitMQ为例,交换机主要支持4种类型:

• Direct , 直接交换机,生产者发送消息时,直接指定要发送到哪个队列上;交换机收到消息后,如果绑定了该队列,就会把消息发过去,如果没有就丢弃该消息.?
• Fanout , 扇出交换机,交换机收到生产者发送的消息,会将该消息发送到所有绑定的队列上.
• Topic ,主题交换机,队列绑定到交换机上时,指定一个字符串为BindingKey,消息被发送到交换机上时,指定一个字符串为RoutingKey,如果这两个字符串满足一定的匹配条件,则交换机将该消息投递到相应队列.
• Header,这种交换机的类型比较复杂,也比较难实现,我们就不做过多介绍了.

1.4 Broker的核心API

在我们实现的消息队列项目中,Broker是至关重要的,它要实现下列几个核心API,供生产者/消费者调用.

1. 创建队列(queueDeclare),这里的"创建"指的是没有则创建,有就啥也不干

2. 删除队列(queueDelete)

3. 创建交换机(exchangeDeclare),同上queueDeclare

4. 删除交换机(exchangeDelete)

5. 创建绑定(queueBind)

6. 解除绑定(queueUnbind)

7. 发布消息(basicPublish)

8. 订阅消息(basicConsume)

9. 确认消息(basicAck),消费者取走消息并不代表消费者处理了消息,因此需要让消费者告诉Broker,保证处理消息没有遗漏,在收到确认之前,Broker需要保存未确认的消息一段时间.

有的童靴可能会问,我们刚才提到的概念中,有"消费"这一概念,为啥没有提供相应的API呢?

很简单,因为RabbitMQ没有支持...

如果没有提供消费的API,Broker和Consumer的工作模式有两种:

1. Push,Broker主动把message发送给消费者,这种模式下MQ削峰填谷的作用不大(RabbitMQ支持)

2. Pull,消费者主动获取数据(这种模式下,message的时效性不高)

由于我们是以RabbitMQ为蓝图的,因此我们使用的也是第一种模式.

?1.5 网络通信

和阻塞队列不同,MessageQueue是为不同主机服务的.生产者和消费者都是客户端程序,Broker作为服务器,三者之间通过网络进行通信.

在网络通信的过程中,客户端要提供相应的API,来实现对服务器的操作.

也就是说,客户端的API只负责向服务器发送请求并接收服务器的响应,真正的业务由服务器端的API来做.这种远程调用的方式称为"RPC".

因此,客户端的API除了包含服务器提供的API外,还要有网络通信相关的API

1. 创建Connection,一个Connection对象代表一个TCP连接

2. 关闭Connection

3. 创建Channel,建立/销毁一个连接的成本比较高,Channel只是一个逻辑上的概念,一个Connection可以有多个Channel.

4. 关闭Channel

关于Connection和Channel,可以用下面这个栗子解释...

如果你到医院打针,要输三瓶药水,护士肯定只在你的胳膊上扎一次针,这就相当于建立了一个Connection,然后每换一瓶药水,不会重新扎针,而是用原来的针头,这就是一个Channel的创建.

5. 创建队列

6. 关闭队列

7. 创建交换机

8. 删除交换机

9. 创建绑定

10. 解除绑定

11. 发布消息

12. 订阅消息

13. 确认消息

1.6 消息应答

应答模式分为两种.

1. 自动应答: 消费者消费了消息,就默认应答完毕,Broker直接将该消息删除.

2. 手动应答: 消费者手动调用应答接口,Broker收到应答请求之后,才会将该消息彻底删除.

对于一些不太重要的消息,可以采用第一种方式.RabbitMQ支持了两种应答方式,因此我们的项目也会实现这两种模式.

1.7 模块划分

上面的一堆概念,想必童靴们听懂了但是没办法串联到一起,没关系,可以借助下面一张图来理解.

上面的图示中有几个问题需要解释:?

• 序列化是指将结构化数据转换成无结构的二进制数据,反序列化是指将二进制数据转换成结构化数据.
• 我们要实现的消息队列是一个通用业务,适合所有的生产者/消费者模型,因此网络通信部分由客户端来实现.
• MessageQueue使用内存作为存储空间,硬盘只是辅助存储,用于持久化的时候使用.
• MetaData是指元数据,交换机/队列/绑定等对象需要进行增删改查等操作,由数据库来管理比较合适
• message作为消息主体,数量比较多,如果用数据库来存储,进行增加/删除的时候比较慢,并且消息不需要进行复杂的查找操作,因此使用文件进行管理.
• message的删除只是逻辑删除,(如果是物理删除的话,需要进行文件上的数据移动,速度比较慢),如果有效消息比较少,就需要进行GC操作

二. 硬盘操作

想必童靴们看完上面的概念之后还是很懵逼,下面我们把上面的模块拆开来实现.

2.1 数据库操作

我们先创建一个MetaDataManager类来封装对数据库的操作.在前面提到过,数据库是用来管理交换机,队列和绑定的,它们统称为"meta data".下面是MetaDataManager类提供的接口.

• ? createExchange: 创建交换机
• ? deleteExchange: 删除交换机
• ? selectAllExchanges: 查询所有交换机,因为Broker Server的存储分为两部分,内存和硬盘,重启服务器时需要从硬盘恢复数据,用到了该方法.
• ? createQueue: 创建队列
• ? deleteQueue: 删除队列
• ? selectAllQueues: 查询全部队列
• ? createBinding: 创建绑定
• ? deleteBinding: 删除绑定
• ? selectAllBindings: 查询全部绑定
• ? createTables: 创建exchange表,queue表,binding表
• ? createDefaultData: RabbitMQ本身就存在一个交换机,类型是直接交换机,名字是"",可持久化,因此我们也实现一个匿名交换机.
• ? init: 封装createTables和createDefaultData方法
• ? deleteDB: 删除这个数据库的相关文件,便于测试数据的时候使用,防止每次测试时数据的污染.
• ?checkDBExists: 方便测试

2.1.1 SQLite数据库配置

对于Exchange,Queue,Binding,我们使用SQLite数据库持久化保存.

相比于MySQL,SQLite更轻量,只需要一个.exe文件即可运行.因为我们创建的是SpringBoot项目,只需要引入相关依赖,这个项目就会自动加载jar包和dll动态库文件,就能直接运行SQLite数据库了.

另外,因为我们要使用MyBatis来操作数据库,所以在pom.xml中也要引入mybatis依赖

下面是application.yml的相关配置.

spring:
  datasource:
    #表示将数据库建在data目录下的meta.db文件中,基准目录是该项目所在的目录
    url: jdbc:sqlite:./data/meta.db 
    # SQLite不需要用户名和密码,因为SQLite不是一个C/S结构的数据库,它只在本地运行,所以不需要验证
    username:
    password:
    # 数据库的驱动类
    driver-class-name: org.sqlite.JDBC


#mybatis的起手配置
mybatis:
  mapper-locations: classpath:mapper/*Mapper.xml 
  configuration:
    #    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #此处不打印对数据库操作的日志了,测试的时候可以打印一下
    map-underscore-to-camel-case: true

?2.1.2 Meta相关类的创建

先来创建Queue,Exchange,Binding类.

@Data
public class QueueEntity {
    //队列的唯一标识
    private String name;
    //是否可持久化
    private boolean durable=false;
    //如果没有消费者订阅这个队列,是否自动删除
    private boolean autoDelete=false;
    //是否为某个消费者私有
    private boolean exclusive=false;
    //额外参数
    private Map<String,Object> arguments=new HashMap<>();
}

@Data
public class Exchange {
    //交换机的唯一标识
    private String name;
    //交换机类型,默认是直接交换机
    private ExchangeType type=ExchangeType.DIRECT;
    //是否持久化
    private boolean durable=false;
    //如果没有队列绑定这个交换机,是否自动删除该交换机(暂时不实现)
    private boolean autoDelete=false;
    //额外参数
    private Map<String,Object> arguments=new HashMap<>();
}

/**
 * 定义交换机类型,1表示直接交换机,2表示扇出交换机,3表示主题交换机
 */
public enum ExchangeType{
    DIRECT(1),
    FANOUT(2),
    TOPIC(3);
    private final int type;
    ExchangeType(int type){
        this.type=type;
    }

    public int getType() {
        return type;
    }
}

@Data
public class Binding {
    private String exchangeName;
    private String queueName;
    //交换机根据bindingKey确定要将消息转发给哪些队列
    private String bindingKey;
}

?然后我们定义MetaMapper类进行数据库的ACUD操作.

@Mapper
public interface MetaMapper {
    //创建相关的表
    //因为涉及到服务器的重启操作,每次都要重新进行建库建表比较麻烦,所以调用代码来执行
    @Insert("create table if not exists exchange(" +
            "name varchar(50) primary key," +
            "type int," +
            "durable boolean," +
            "auto_delete boolean," +
            "arguments varchar(1024)"+
            ")")
    void createExchangeTable();

    @Insert("create table if not exists queue(" +
            "name varchar(50) primary key," +
            "durable boolean,"+
            "auto_delete boolean," +
            "exclusive boolean," +
            "arguments varchar(1024)" +
            ")")
    void createQueueTable();

    @Insert("create table if not exists binding(" +
            "exchangeName varchar(50)," +
            "queueName varchar(50)," +
            "binding_key varchar(100)" +
            ")")
    void createBindingTable();

    @Insert("insert into exchange values" +
            "(#{name},#{type},#{durable},#{autoDelete},#{arguments})")
    void insertExchange(Exchange exchange);

    @Delete("delete from exchange where name=#{name}")
    void deleteExchange(String name);

    @Insert("insert into queue values" +
            "(#{name},#{durable},#{autoDelete},#{exclusive},#{arguments})")
    void insertQueue(QueueEntity queue);

    @Delete("delete from queue where name=#{name}")
    void deleteQueue(String name);

    @Insert("insert into binding values" +
            "(#{exchangeName},#{queueName},#{bindingKey})")
    void insertBinding(Binding binding);

    @Delete("delete from binding where exchangeName=#{exchangeName} and queueName=#{queueName}")
    void deleteBinding(Binding binding);

    @Select("select * from exchange")
    List<Exchange> selectAllExchanges();

    @Select("select * from queue")
    List<QueueEntity> selectAllQueues();

    @Select("select * from binding")
    List<Binding> selectAllBindings();
}

因为Queue和Mapper中的Arguments是一个Map对象,没办法直接插入到数据库中,只能先转换成字符串.所以需要多写两个这两个类的get和set方法.

有些同学可能会疑惑,我们使用了@Data注解,自己再创建一个get和set,不会冲突吗?

如果我们自己创建了get和set,Lombok就不会再帮助我们生成了

//在Exchange和Queue类中添加如下方法   
 @SneakyThrows
    public void setArguments(String jsonString){
        ObjectMapper mapper=new ObjectMapper();
        this.arguments=mapper.readValue(jsonString, new TypeReference<Map<String, Object>>() {});
    }

    @SneakyThrows
    public String getArguments(){
        ObjectMapper mapper=new ObjectMapper();
        return mapper.writeValueAsString(arguments);
    }
   /**
     * 为了方便测试
     */
    public void setArguments(String key,Object value){
        arguments.put(key,value);
    }
    public Object getArguments(String key){
        return arguments.get(key);
    }
    /**
     * 上层调用时可能会传入一个真正的Map作为额外参数
     */
    public void setArguments(Map<String,Object> arguments){
        this.arguments=arguments;
    }

接下来就可以创建MetaManager类来进行对MetaMapper的封装了.

@Data
@Slf4j
public class MetaManager {
    private MetaMapper metaMapper;
    public void insertExchange(Exchange exchange){
        metaMapper.insertExchange(exchange);
    }
    public void deleteExchange(String exchangeName){
        metaMapper.deleteExchange(exchangeName);
    }
    public void insertQueue(QueueEntity queue){
        metaMapper.insertQueue(queue);
    }
    public void deleteQueue(String queueName){
        metaMapper.deleteQueue(queueName);
    }
    public void insertBinding(Binding binding){
        metaMapper.insertBinding(binding);
    }
    public void deleteBinding(Binding binding){
        metaMapper.deleteBinding(binding);
    }
    public List<Exchange> selectAllExchanges(){
        return metaMapper.selectAllExchanges();
    }
    public List<QueueEntity> selectAllQueues(){
        return metaMapper.selectAllQueues();
    }
    public List<Binding> selectAllBindings(){
        return metaMapper.selectAllBindings();
    }

    /**
     * 进行建库建表操作
     * 1.建库,MyBatis进行数据库的操作的时候会自动建库
     * 2.建表,需要手动完成
     */
    public void init(){
        //因为我们不需要将MetaManager交给Spring管理,但是如果想获取到MetaMapper对象就必须从Spring中取,所以采用下面的方式
        this.metaMapper= DemoApplication.context.getBean(MetaMapper.class);
        //如果数据库已经存在,就不需要再次建立
        if(checkDBExists()){
            log.info("数据库已经存在");
        }else{
            //数据库不存在,执行建表操作
            createTables();
            //进行数据的初始化
            createDefaultData();
            log.info("数据库初始化完成");
        }
    }

    /**
     *创建一个默认交换机,name="",type=DIRECT,durable=true
     */
    private void createDefaultData() {
        Exchange exchange=new Exchange();
        exchange.setName("");
        exchange.setDurable(true);
        exchange.setType(ExchangeType.DIRECT);
        exchange.setAutoDelete(false);
        metaMapper.insertExchange(exchange);
    }

    private void createTables() {
        metaMapper.createQueueTable();
        metaMapper.createExchangeTable();
        metaMapper.createBindingTable();
    }


    /**
     * 判断数据库是否存在,就看meta.db是否存在即可
     * @return
     */
    private boolean checkDBExists() {
        File file=new File("./data/meta.db");
        return file.exists();
    }

    /**
     * 每次测试数据之后进行删库操作,防止数据污染
     */
    public void deleteDb(){
        File file=new File("./data/meta.db");
        file.delete();
    }
}

因为MetaManager在初始化的时候需要用到DemoApplication类,所以对这个类的代码稍加修改.

@SpringBootApplication
public class DemoApplication {

	public static ConfigurableApplicationContext context;
	public static void main(String[] args) {
		context=SpringApplication.run(DemoApplication.class, args);
	}

}

?下面是这些类的目录结构,可做参考.

2.1.3 测试MetaManager类

?单元测试是十分必要的,毕竟每个程序猿都不想自己一顿猛如虎的操作之后发现bug都有几千行!下面直接给出单元测试类的代码(仅供参考)

@SpringBootTest
class MetaManagerTest {

    private MetaManager metaManager=new MetaManager();
    @BeforeEach
    void setUp() {
        //因为metaManager初始化的时候需要用到DemoApplication.context,这里需要手动赋值
        DemoApplication.context= SpringApplication.run(DemoApplication.class);
        metaManager.init();
    }

    @Test
    void init() {
        //初始化完成后应该有一个默认交换机
        List<Exchange> exchanges=metaManager.selectAllExchanges();
        Assertions.assertEquals(1,exchanges.size());
        Exchange exchange=exchanges.get(0);
        Assertions.assertEquals("",exchange.getName());
        Assertions.assertEquals(ExchangeType.DIRECT,exchange.getType());
        Assertions.assertEquals(true,exchange.isDurable());
        Assertions.assertEquals(false,exchange.isAutoDelete());
    }
    @AfterEach
    void tearDown() {
        //因为MyBatis正在使用数据库,所以必须把Spring项目关掉之后才可以删除数据库文件
        DemoApplication.context.close();
        metaManager.deleteDb();
    }

    @Test
    void insertExchange() {
        Exchange expectedExchange=new Exchange();
        expectedExchange.setName("testExchange");
        expectedExchange.setType(ExchangeType.TOPIC);
        expectedExchange.setDurable(true);
        expectedExchange.setAutoDelete(false);
        expectedExchange.setArguments("aaa",1);
        metaManager.insertExchange(expectedExchange);

        List<Exchange> exchanges=metaManager.selectAllExchanges();
        Assertions.assertEquals(2,exchanges.size());
        Exchange actualExchange=exchanges.get(1);
        Assertions.assertEquals("testExchange",actualExchange.getName());
        Assertions.assertTrue(actualExchange.isDurable());
        Assertions.assertFalse(actualExchange.isAutoDelete());
        Assertions.assertEquals(ExchangeType.TOPIC,actualExchange.getType());
        Assertions.assertEquals(1,actualExchange.getArguments("aaa"));
    }

    @Test
    void insertQueue() {
        QueueEntity expectedQueue=new QueueEntity();
        expectedQueue.setName("testQueue");
        expectedQueue.setDurable(false);
        expectedQueue.setExclusive(false);
        expectedQueue.setAutoDelete(false);
        expectedQueue.setArguments("bbb",2);
        metaManager.insertQueue(expectedQueue);

        List<QueueEntity> queues=metaManager.selectAllQueues();
        Assertions.assertEquals(1,queues.size());
        QueueEntity actualQueue=queues.get(0);
        Assertions.assertEquals("testQueue",actualQueue.getName());
        Assertions.assertFalse(actualQueue.isAutoDelete());
        Assertions.assertFalse(actualQueue.isDurable());
        Assertions.assertFalse(actualQueue.isExclusive());
        Assertions.assertEquals(2,actualQueue.getArguments("bbb"));
    }

    @Test
    void insertBinding() {
        Binding expectedBinding=new Binding();
        expectedBinding.setExchangeName("testExchange");
        expectedBinding.setQueueName("testQueue");
        expectedBinding.setBindingKey("bindingKey");
        metaManager.insertBinding(expectedBinding);

        List<Binding> bindings=metaManager.selectAllBindings();
        Assertions.assertEquals(1,bindings.size());
        Binding  actualBinding=bindings.get(0);
        Assertions.assertEquals("testQueue",actualBinding.getQueueName());
        Assertions.assertEquals("testExchange",actualBinding.getExchangeName());
        Assertions.assertEquals("bindingKey",actualBinding.getBindingKey());
    }

    @Test
    void deleteExchange() {
        Exchange expectedExchange=new Exchange();
        expectedExchange.setName("testExchange");
        expectedExchange.setType(ExchangeType.TOPIC);
        expectedExchange.setDurable(true);
        expectedExchange.setAutoDelete(false);
        expectedExchange.setArguments("aaa",1);
        metaManager.insertExchange(expectedExchange);

        List<Exchange> exchanges=metaManager.selectAllExchanges();
        Assertions.assertEquals(2,exchanges.size());

        metaManager.deleteExchange("testExchange");
        exchanges=metaManager.selectAllExchanges();
        Assertions.assertEquals(1,exchanges.size());
    }

    @Test
    void deleteQueue() {
        QueueEntity expectedQueue=new QueueEntity();
        expectedQueue.setName("testQueue");
        expectedQueue.setDurable(false);
        expectedQueue.setExclusive(false);
        expectedQueue.setAutoDelete(false);
        expectedQueue.setArguments("bbb",2);
        metaManager.insertQueue(expectedQueue);

        List<QueueEntity> queues=metaManager.selectAllQueues();
        Assertions.assertEquals(1,queues.size());
        metaManager.deleteQueue("testQueue");
        queues=metaManager.selectAllQueues();
        Assertions.assertEquals(0,queues.size());
    }

    @Test
    void deleteBinding() {

        Binding expectedBinding=new Binding();
        expectedBinding.setExchangeName("testExchange");
        expectedBinding.setQueueName("testQueue");
        expectedBinding.setBindingKey("bindingKey");
        metaManager.insertBinding(expectedBinding);

        List<Binding> bindings=metaManager.selectAllBindings();
        Assertions.assertEquals(1,bindings.size());
        Binding binding=new Binding();
        binding.setExchangeName("testExchange");
        binding.setQueueName("testQueue");
        metaManager.deleteBinding(binding);
        bindings=metaManager.selectAllBindings();
        Assertions.assertEquals(0,bindings.size());
    }


}

?2.2 文件操作

前面我们提到过,Message的持久化需要放进文件里,因为message的数量比较多,如果使用数据库来存储,性能会变慢; 并且message不需要复杂的增删改查,不需要用到数据库

2.2.1 Message相关类的创建

既然要操作的是Message,我们肯定要定义一个Message类了.

@Data
public class Message implements Serializable {
    //message的基本属性
    private BasicProperties basicProperties;
    //message存放的消息内容,因为涉及到网络传输和文件存储,使用字节数组存储比较合适
    private byte[] body;

    //辅助成员
    //表示在文件中的起始/终止位置,方便把该消息读取/存放到文件里
    //这两个属性没有必要存放在文件里,使用transient关键字,就不会被序列化
    private transient long offsetBegin;
    private transient long offsetEbd;

    //表示该消息是否有效,1表示有效,0表示无效
    private byte isValid=0x1;

    //因为消息的数目比较多,所以使用工厂方法,messageId由系统自动生成,以"M-"作为前缀
    public static Message createMessageWithId(String routingKey,BasicProperties properties,byte[] body){
        Message message=new Message();
        //一般properties传的参数都是null
        if(properties!=null){
            message.setBasicProperties(properties);
        }
        message.setMessageId(generateMessageId());
        message.setRoutingKey(routingKey);
        message.setBody(body);
        return message;
    }

    private static String generateMessageId() {
        return "M-"+ UUID.randomUUID();
    }

    /**
     * 提供操作基本属性的接口,方便外界调用
     * @param messageId
     */
    public void setMessageId(String messageId){
        basicProperties.setMessageId(messageId);
    }
    public String getMessageId(){
        return basicProperties.getMessageId();
    }
    public void setRoutingKey(String routingKey){
        basicProperties.setRoutingKey(routingKey);
    }
    public String getRoutingKey(){
        return basicProperties.getRoutingKey();
    }
    public boolean isDelivery() {
        return (basicProperties.getDelivery() == 0x2);
    }
    public void setDelivery(byte delivery){
        basicProperties.setDelivery(delivery);
    }
}

@Data
public class BasicProperties implements Serializable {
    //消息的唯一标识
    private String messageId;
    //交换机根据routingKey转发该消息
    private String routingKey;
    //是否持久化 1表示非持久化 2表示持久化
    private byte delivery=0x1;
}

?因为message是存放在Queue上的,所以我们需要为每个Queue创建一个目录目录名即为队列名,这个目录下有两个文件:

1. queue_data.txt,用来存放这个队列的全部消息,以二进制的方式存储
2. queue_stat.txt,用来统计这个队列的统计信息,方便进行GC操作

我们再来创建一个MessageFileManager类,用来操作message相关的文件.

?下面定义一下这个类要提供的接口

1. readStat: 读取统计文件
2. writeStat: 写入统计文件
3. sendMessage: 向某个队列的data文件中写入消息
4. deleteMessage: 删除某个队列的某条消息(逻辑删除)
5. checkGC: 规定当消息总数超过1500,有效消息数低于50%时进行GC操作
6. GC: 将该队列中的无效消息物理清空
7. createQueueFiles: 创建队列对应的目录和文件
8. deleteQueueFiles: 删除队列对应的目录和文件
9. loadMessages: 从文件上获取某队列的全部有效消息,方便服务器重启后进行恢复操作?

?2.2.2 Queue对应文件规定

以队列为维度创建文件,每个队列都有一个目录,目录的名字为队列名,这个目录存放在data目录下,形如./data/testQeue,每个目录包含两个文件:

• queue_data.txt: 二进制文件,用来存放消息的内容
• queue_stat.txt: 文本文件,用来保存消息的统计信息

下面我们来规定一下这两种文件的格式.

现在看stat文件吧,它比较简单.

再来定义data文件

• 它是二进制文件,文件后缀是啥无所谓,这是window用来区分文件格式的方式
• 每个消息使用二进制的方式存储
• 每个消息分成两部分,第一部分存储该消息的长度(以字节为单位),这一部分占4byte,第二部分存储该消息的内容
• 消息之间首尾相连,没有分隔符

规定,当一个队列中的总消息数超过1500,且有效消息数低于50%时,就要进行GC操作,防止因为文件过大导致性能降低.

2.2.3 MessageFileManager类的创建

下面让我们一起来实现一下这个类,配合注释看更下饭哦~

@Data
@Slf4j
public class MessageFileManager {
    //定义统计文件对应的类
    public static class Stat{
        public int totalCount;
        public int validCount;
    }

    /**
     * MessageFileManager的初始化方法,实际上啥也没干,为了方便代码扩展
     */
    public void init(){}
    /**
     * @param queueName
     * @return 返回队列对应的目录名
     */
    private String getQueueDirPath(String queueName){
        return "./data/"+queueName;
    }

    /**
     * @param queueName
     * @return 返回队列对应的data文件名
     */
    private String getQueueDataPath(String queueName){
        return getQueueDirPath(queueName)+"/queue_data.txt";
    }

    /**
     * @param queueName
     * @return 返回队列对应的统计文件名
     */
    private String getQueueStatPath(String queueName){
        return getQueueDirPath(queueName)+"/queue_stat.txt";
    }

    /**
     * 创建队列对应的文件,因为如果有则不创建,所以不用加锁
     * @param queueName
     */
    public void createQueueFiles(String queueName) throws IOException {
        File dir=new File(getQueueDirPath(queueName));
        if(!dir.exists()){
            boolean ok=dir.mkdirs();//有该目录则不创建,没有就创建
            if(!ok){
                throw new IOException("[MessageFileManager] 创建队列目录失败,queueName="+queueName);
            }
        }
        File dataFile=new File(getQueueDataPath(queueName));
        if(!dataFile.exists()){
            boolean ok=dataFile.createNewFile();
            if(!ok){
                throw new IOException("[MessageFileManager] 创建队列的data文件失败,queue_data.txt="+getQueueDataPath(queueName));
            }
        }
        File statFile=new File(getQueueStatPath(queueName));
        if(!statFile.exists()){
            boolean ok=statFile.createNewFile();
            if(!ok){
                throw new IOException("[MessageFileManager] 创建队列的stat文件失败,queue_stat.txt="+getQueueStatPath(queueName));
            }
        }
        //给统计文件写入初始数据,后续操作stat文件时不用对空文件进行判定
        Stat stat=new Stat();
        stat.totalCount=0;
        stat.validCount=0;
        writeStat(queueName,stat);
    }

    /**
     * 删除队列对应的文件,因为删除失败也没啥影响,所以就不加锁了
     */
    public void deleteQueueFiles(String queueName) throws IOException {
        File dataFile=new File(getQueueDataPath(queueName));
        boolean ok1= dataFile.delete();
        File statFile=new File(getQueueStatPath(queueName));
        boolean ok2=statFile.delete();
        File dir= new File(getQueueDirPath(queueName));
        boolean ok3= dir.delete();
        if(!ok1||!ok2||!ok3){
            throw new IOException("[MessageFileManager] 删除队列文件失败,queueName="+queueName);
        }
    }
    /**
     * 对统计文件进行写操作
     * 本来对文件进行读写操作是要加锁的,但是外层调用者加了,这里就不加了
     * @param queueName
     * @param stat
     */
    private void writeStat(String queueName,Stat stat) {
        try(OutputStream outputStream=new FileOutputStream(getQueueStatPath(queueName));
            PrintWriter writer=new PrintWriter(outputStream)){
            writer.write(stat.totalCount+"\t"+ stat.validCount);
            writer.flush();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 对统计文件进行读操作
     * @param queueName
     * @return
     */
    private Stat readStat(String queueName){
        Stat stat=null;
        try(InputStream inputStream=new FileInputStream(getQueueStatPath(queueName));
            Scanner scanner=new Scanner(inputStream)) {
            stat=new Stat();
            stat.totalCount=scanner.nextInt();
            stat.validCount=scanner.nextInt();
            return stat;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return stat;
    }
    /**
     * 发送消息
     * 1. 得到消息的offsetBegin和offsetEnd
     * 2. 将该消息写到data文件上
     * 3. 更新stat文件
     */
    public void sendMessage(QueueEntity queue, Message message) throws MqException, IOException {
        //涉及到多线程,要进行加锁
        synchronized (queue){
            //先检查这个队列对应的文件是否存在
            if(!isExists(queue.getName())){
                throw new MqException("[MessageFileManager] sendMessage,要发送的队列文件不存在");
            }
            File dataFile=new File(getQueueDataPath(queue.getName()));
            //先更新message的offsetBegin和offsetEnd
            long fileLength=dataFile.length();
            byte[] messageBinary= BinaryTool.toBytes(message);
            message.setOffsetBegin(fileLength+4);
            message.setOffsetEnd(fileLength+messageBinary.length+4);
            //再进行文件写入
            //outPutStream打开文件时会默认清空原有内容,需要将append参数设置为true
            try(OutputStream outputStream=new FileOutputStream(dataFile,true);
            DataOutputStream dataOutputStream=new DataOutputStream(outputStream)){
                //先写入长度,使用DataOutputStream类,固定写4byte
                dataOutputStream.writeInt(messageBinary.length);
                //再写二进制的message
                dataOutputStream.write(messageBinary);
            }
            //更新stat文件
            Stat stat=readStat(queue.getName());
            stat.totalCount++;
            stat.validCount++;
            writeStat(queue.getName(),stat);
        }
        log.info("硬盘已成功添加message,queueName="+queue.getName()+",messageId="+message.getMessageId());
    }

    /**
     * 逻辑删除message: 1.将isValid字段置为0x0 2.把这个消息写回去 3.更新统计文件
     * @param queue
     * @param message 这个message是内存传过来的
     */
    public void deleteMessage(QueueEntity queue,Message message) throws MqException, IOException, ClassNotFoundException {
        synchronized (queue){
            if(!isExists(queue.getName())){
                throw new MqException("[MessageFileManager] deleteMessage,消息所在的队列文件不存在");
            }
            //根据消息的offsetBegin和offsetEnd字段找到这条消息
            File dataFile=new File(getQueueDataPath(queue.getName()));
            //采用随机读取的方法,读取方式为写和读
            try(RandomAccessFile randomAccessFile=new RandomAccessFile(dataFile,"rw")){
                //先找到该消息的起始位置
                randomAccessFile.seek(message.getOffsetBegin());
                //将这个对象的isValid设置为0x0
                message.setIsValid((byte) 0x00);
                //将message转换成字节数组
                byte[] bodyDest=BinaryTool.toBytes(message);
                //将这个数组写入文件
                randomAccessFile.write(bodyDest);
            }
            Stat stat=readStat(queue.getName());
            stat.validCount--;
            writeStat(queue.getName(),stat);
        }
        log.info("已删除硬盘上的message,queueName="+queue.getName()+",messageId="+message.getMessageId());
    }
    /**
     * 判断某个队列对应的文件是否存在
     * @param queueName
     * @return
     */
    private boolean isExists(String queueName) {
        File dir=new File(getQueueDirPath(queueName));
        if(!dir.isDirectory()){
            return false;
        }
        File dataFile=new File(getQueueDataPath(queueName));
        if(!dataFile.isFile()){
            return false;
        }
        File statFile=new File(getQueueStatPath(queueName));
        if(!statFile.isFile()){
            return false;
        }
        return true;
    }

    /**
     * 从硬盘上加载queue存放的全部Message,服务器重启(只有一个线程)/GC操作(GC方法已经加过锁了)会调用该方法,所以可以不用加锁
     * @param queueName
     * @return 返回LinkedList,方便进行头删
     */
    public LinkedList<Message> loadMessages(String queueName) throws MqException, IOException, ClassNotFoundException {
        //synchronized (queue){
            if(!isExists(queueName)) {
                throw new MqException("[MessageFileManager] loadQueueMessages,要加载的队列文件不存在!");
            }
            LinkedList<Message> messages=new LinkedList<>();
            //记录当前message的位置
            long currentSet=0;
            try(InputStream inputStream=new FileInputStream(getQueueDataPath(queueName));
            DataInputStream dataInputStream=new DataInputStream(inputStream)){
                while(true){
                    //先读取消息的长度
                    int expectedLength=dataInputStream.readInt();
                    byte[] body=new byte[expectedLength];
                    int actualLength=dataInputStream.read(body);
                    if(actualLength!=expectedLength){
                        throw new MqException("[MessageFileManager] 消息存储的格式不正确!");
                    }
                    //转换成消息对象
                    Message message=(Message) BinaryTool.fromBytes(body);
                    if(message.getIsValid()==0x0){
                        //这个消息是无效的
                        currentSet+=4+body.length;
                        continue;
                    }
                    //设置辅助属性
                    currentSet+=4;
                    message.setOffsetBegin(currentSet);
                    currentSet+=actualLength;
                    message.setOffsetEnd(currentSet);
                    messages.add(message);
                }
            }catch (EOFException e){
                //dataInputStream读到文件结尾时,会抛出EOFException异常
                log.info("成功加载该队列的全部消息,queueName="+queueName);
            }
            return messages;
        //}
    }
    /**
     * 判断是否要进行GC操作,由上层调用,所以修饰符为public
     * total>1500&&valid<750时触发GC
     */
    public boolean checkGC(String queueName){
        //根据统计文件判断
        Stat stat=readStat(queueName);
        if(stat.totalCount>1500&&stat.validCount*1.0 / stat.totalCount<0.5){
            return true;
        }else {
            return false;
        }
    }
    /**
     * 进行GC操作
     * 1. 创建一个新的data文件,queue_data_new.txt
     * 2. 读取旧文件的全部有效message
     * 3. 将message加载到新文件上
     * 4. 将新文件重命名
     * 5. 修改统计文件
     */
    public void GC(QueueEntity queue) throws MqException, IOException, ClassNotFoundException {
        synchronized (queue){
            //统计一下GC耗时
            long start=System.currentTimeMillis();
           File newDataFile=new File(getQueueNewDataPath(queue.getName()));
           if(newDataFile.exists()){
               //可能上一次GC的时候没删掉,抛异常
               throw new MqException("[MessageFileManager] GC时新文件已存在,queue_data_new.txt="+getQueueNewDataPath(queue.getName()));
           }
           boolean ok=newDataFile.createNewFile();
           if(!ok){
               throw new IOException("[MessageFileManager] 无法创建新的data文件,queue_data_new,txt="+getQueueNewDataPath(queue.getName()));
           }
           //从旧文件中加载全部有效message
            List<Message> messages=loadMessages(queue.getName());
            //将加载的message写到新文件中
            try(OutputStream outputStream=new FileOutputStream(getQueueNewDataPath(queue.getName()));
            DataOutputStream dataOutputStream=new DataOutputStream(outputStream)){
                for(Message message:messages){
                    byte[] body=BinaryTool.toBytes(message);
                    dataOutputStream.writeInt(body.length);
                    dataOutputStream.write(body);
                }
            }
            //让新文件取代旧文件
            File oldDataFile=new File(getQueueDataPath(queue.getName()));
            ok=oldDataFile.delete();
            if(!ok){
                throw new IOException("[MessageFileManager] 无法删除旧文件,queue_data.txt="+getQueueDataPath(queue.getName()));
            }
            ok=newDataFile.renameTo(oldDataFile);
            if(!ok){
                throw new IOException("[MessageFileManager] 新文件重命名失败,queueName="+queue.getName());
            }
            //更新统计文件
            Stat stat=new Stat();
            stat.totalCount= messages.size();
            stat.validCount= messages.size();
            readStat(queue.getName());
            long end=System.currentTimeMillis();
            log.info("GC耗时: "+(end-start)+"ms");
        }
    }

    private String getQueueNewDataPath(String queueName) {
        return getQueueDirPath(queueName)+"/queue_data_new.txt";
    }
}

2.2.4 测试MessageFileManager类

下面是单元测试的代码.(仅供参考,童靴们可以写更多的测试案例)

@SpringBootTest
class MessageFileManagerTest {

    private MessageFileManager fileManager=new MessageFileManager();
    private final String queueName1="testQueue1";
    private final String queueName2="testQueue2";
    @BeforeEach
    void setUp() throws IOException {
        //创建队列文件,队列名为testQueue
        fileManager.init();
        fileManager.createQueueFiles(queueName1);
        fileManager.createQueueFiles(queueName2);
    }

    @AfterEach
    void tearDown() throws IOException {
        //销毁队列对应的文件
        fileManager.deleteQueueFiles(queueName1);
        fileManager.deleteQueueFiles(queueName2);
    }

    @Test
    void createQueueFiles() {
        //检查两个队列的文件是否已经创建好
        //利用反射调用isExists方法
        Boolean ok1=ReflectionTestUtils.invokeMethod(fileManager,"isExists",queueName1);
        Boolean ok2=ReflectionTestUtils.invokeMethod(fileManager,"isExists",queueName2);
        Assertions.assertTrue(ok1);
        Assertions.assertTrue(ok2);
    }

    private QueueEntity createQueue(String queueName){
        QueueEntity queue=new QueueEntity();
        queue.setName(queueName);
        return queue;
    }
    private Message createMessage(String routingKey,String content){
        Message message=Message.createMessageWithId(routingKey,null,content.getBytes());
        return message;
    }
    @Test
    void sendMessage() throws IOException, MqException, ClassNotFoundException {
        QueueEntity queue=createQueue(queueName1);
        Message message=createMessage("testRoutingKey","hello");
        fileManager.sendMessage(queue,message);
        LinkedList<Message> messages=fileManager.loadMessages(queueName1);
        Assertions.assertEquals(1,messages.size());
        Message message1=messages.get(0);
        Assertions.assertEquals("testRoutingKey",message1.getRoutingKey());
        Assertions.assertEquals(message.getMessageId(),message1.getMessageId());
        Assertions.assertArrayEquals(message.getBody(),message1.getBody());
    }


    @Test
    void loadMessages() throws IOException, MqException, ClassNotFoundException {
        QueueEntity queue=createQueue(queueName1);
        List<Message> exceptedMessages=new ArrayList<>();
        for(int i=0;i<10;i++){
            Message message=createMessage("testRoutingKey","content"+i);
            exceptedMessages.add(message);
            fileManager.sendMessage(queue,message);
        }


        for(int i=0;i<10;i+=2){
            fileManager.deleteMessage(queue,exceptedMessages.get(i));
        }
        List<Message> actualMessages=fileManager.loadMessages(queueName1);
        for(int i=0;i<actualMessages.size();i++){
            Message exceptedMsg=exceptedMessages.get(i*2+1);
            Message actualMsg=actualMessages.get(i);
            Assertions.assertEquals(exceptedMsg.getMessageId(),actualMsg.getMessageId());
            Assertions.assertEquals(exceptedMsg.getRoutingKey(),actualMsg.getRoutingKey());
            Assertions.assertArrayEquals(exceptedMsg.getBody(),actualMsg.getBody());
            Assertions.assertEquals(exceptedMsg.getOffsetBegin(),actualMsg.getOffsetBegin());
            Assertions.assertEquals(exceptedMsg.getOffsetEnd(),actualMsg.getOffsetEnd());
        }
    }

    @Test
    void GC() throws IOException, MqException, ClassNotFoundException {
        //先插入几个message
        QueueEntity queue=createQueue(queueName1);
        List<Message> messages=new ArrayList<>();
        for(int i=0;i<10;i++){
            Message message=createMessage("testRoutingKey","content"+i);
            fileManager.sendMessage(queue,message);
            messages.add(message);
        }
        //删除后五个message
        for(int i=5;i<10;i++){
            fileManager.deleteMessage(queue,messages.get(i));
        }
        //修改stat文件,因为是私有方法,这里使用反射
        MessageFileManager.Stat stat=new MessageFileManager.Stat();
        stat.totalCount=2000;
        stat.validCount=5;
        ReflectionTestUtils.invokeMethod(fileManager,"writeStat",queueName1,stat);
        assertTrue(fileManager.checkGC(queueName1));
        fileManager.GC(queue);
        List<Message> lastMessages=fileManager.loadMessages(queueName1);
        assertEquals(5,lastMessages.size());
        for(int i=0;i<5;i++){
            Message actualMsg=lastMessages.get(i);
            Message expectedMsg=messages.get(i);
            assertEquals(expectedMsg.getMessageId(),actualMsg.getMessageId());
            assertEquals(expectedMsg.getRoutingKey(),actualMsg.getRoutingKey());
            assertArrayEquals(expectedMsg.getBody(),actualMsg.getBody());
            assertEquals(expectedMsg.getOffsetBegin(),actualMsg.getOffsetBegin());
            assertEquals(expectedMsg.getOffsetEnd(),actualMsg.getOffsetEnd());
        }
    }
}

2.3 硬盘操作的封装

? 为了便于虚拟主机调用硬盘操作上的方法,我们对硬盘上的操作进行封装,分为对数据库的操作和对文件的操作.

需要创建一个DiskManager类,下面是这个类的源码.因为MessageFileManager和MetaManager类我们之前已经检测过了,DiskManager类只是对这两个类封装了一层,所以就不进行单元测试了.

@Slf4j
public class DiskManager {
    private MessageFileManager messageFileManager=new MessageFileManager();
    private MetaManager metaManager=new MetaManager();
    public void init(){
        metaManager.init();
        messageFileManager.init();
    }

    //封装对交换机的操作
    public void insertExchange(Exchange exchange){
        metaManager.insertExchange(exchange);
        log.info("硬盘成功添加交换机,exchangeName="+exchange.getName());
    }
    public void deleteExchange(String exchangeName){
        metaManager.deleteExchange(exchangeName);
        log.info("硬盘成功删除交换机,exchangeName="+exchangeName);
    }
    public List<Exchange> selectAllExchanges(){
        return metaManager.selectAllExchanges();
    }
    //对队列的封装
    public void insertQueue(QueueEntity queue) throws IOException {
        metaManager.insertQueue(queue);
        log.info("硬盘成功添加队列,queueName"+queue.getName());
        //同时创建这个队列的文件
        messageFileManager.createQueueFiles(queue.getName());
    }
    public void deleteQueue(String queueName) throws IOException {
        metaManager.deleteQueue(queueName);
        log.info("硬盘成功删除队列,queueName="+queueName);
        //同时删除这个队列的文件
        messageFileManager.deleteQueueFiles(queueName);
    }
    public List<QueueEntity> selectAllQueues(){
        return metaManager.selectAllQueues();
    }
    //对绑定的封装
    public void insertBinding(Binding binding){
        metaManager.insertBinding(binding);
        log.info("硬盘成功添加绑定,binding="+binding);
    }
    public void deleteBinding(Binding binding){
        metaManager.deleteBinding(binding);
        log.info("硬盘成功删除绑定,binding="+binding);
    }
    public List<Binding> selectAllBindings(){
        return metaManager.selectAllBindings();
    }
    //对message的封装
    public void sendMessage(QueueEntity queue,Message message) throws IOException, MqException {
        messageFileManager.sendMessage(queue,message);
    }
    public void deleteMessage(QueueEntity queue,Message message) throws IOException, MqException, ClassNotFoundException {
        messageFileManager.deleteMessage(queue,message);
        //检查是否要进行GC操作
        if(messageFileManager.checkGC(queue.getName())){
            messageFileManager.GC(queue);
        }
    }
    public LinkedList<Message> loadAllMessages(String queueName) throws IOException, MqException, ClassNotFoundException {
        return messageFileManager.loadMessages(queueName);
    }
}

三. 内存操作

3.1 MemoryManager类的实现

在概念篇中提到过,对于Broker Server来说,内存是主要的存储介质,硬盘只是辅助存储,用来进行数据恢复的.下面就创建一个MemoryManager类,用于管理内存中的数据.????????

?下图是MemoryManager提供的API.

先来给出MemoryManager的成员变量,根据它们更容易理解为啥要提供这些API

public class MemoryManager {
    //考虑到线程安全,用到哈希表这个结构时使用ConcurrentMap
    //交换机的哈希表,key=exchangeName
    private ConcurrentHashMap<String, Exchange> exchangesMap=new ConcurrentHashMap<>();
    //队列的哈希表,key=queueName
    private ConcurrentHashMap<String, QueueEntity> queuesMap=new ConcurrentHashMap<>();
    //绑定的hash表,因为交换机需要根据routingKey和bindingKey之间的对应关系将message投递到指定队列,所以第一个Key=exchangeName,第二个key=queueName
    private ConcurrentHashMap<String,ConcurrentHashMap<String, Binding>> bindingsMap=new ConcurrentHashMap<>();
    //message的hash表,因为消息是以队列为维度进行存储的,所以一个队列对应存储的一串消息,key=queueName
    //使用LinkedList,方便进行头删
    private ConcurrentHashMap<String, LinkedList<Message>> queueMessagesMap=new ConcurrentHashMap<>();
    //每个队列的消息被取出后,要等待客户端确认才能彻底删除,所以需要有一个数据结构专门存储未确认的消息
    //为了方便找到未确认的消息并进行删除,使用hash结构,第一个key是queueName,第二个key是messageId
    private ConcurrentHashMap<String,ConcurrentHashMap<String,Message>> queueMessagesWaitAckMap=new ConcurrentHashMap<>();
    //消息中心,用来存放全部的消息,key=messageId
    private ConcurrentHashMap<String,Message> messagesCenter=new ConcurrentHashMap<>();
}

• ?insertExchange: 向内存中添加一个交换机
• deleteExchange: 删除内存中的一个交换机
• getExchange: 查询内存中的某个交换机
• insertQueue: 向内存中插入一个队列
• deleteQueue: 删除内存中的某个队列
• getQueue: 查询内存中的某个队列
• insertBinding: 插入一个绑定
• deleteBinding: 删除一个绑定
• getBinding: 查询一个绑定
• insertMessage: 向消息中心插入一个消息
• deleteMessage: 从消息中心删除一个消息
• getMessage: 从消息中心查询一个消息
• sendMessageToQueue: 向某个队列投递一条消息
• getMessageFromQueue: 得到某个队列的第一条消息,并且从队列中删除该消息
• loadDiskData: 从硬盘上恢复数据
• insertMessageWaitAck: 向某个队列的未确认消息队列中插入一条数据
• deleteMessageWaitAck: 某条消息收到确认后删除该消息
• getMessageWaitAck: 查找某个队列的未确认消息

下面一起来实现这个类吧.

?该说的话都放在注释里了~~

@Data
@Slf4j
public class MemoryManager {
    //考虑到线程安全,用到哈希表这个结构时使用ConcurrentMap
    //交换机的哈希表,key=exchangeName
    private ConcurrentHashMap<String, Exchange> exchangesMap=new ConcurrentHashMap<>();
    //队列的哈希表,key=queueName
    private ConcurrentHashMap<String, QueueEntity> queuesMap=new ConcurrentHashMap<>();
    //绑定的hash表,因为交换机需要根据routingKey和bindingKey之间的对应关系将message投递到指定队列,所以第一个Key=exchangeName,第二个key=queueName
    private ConcurrentHashMap<String,ConcurrentHashMap<String, Binding>> bindingsMap=new ConcurrentHashMap<>();
    //message的hash表,因为消息是以队列为维度进行存储的,所以一个队列对应存储的一串消息,key=queueName
    //使用LinkedList,方便进行头删
    private ConcurrentHashMap<String, LinkedList<Message>> queueMessagesMap=new ConcurrentHashMap<>();
    //每个队列的消息被取出后,要等待客户端确认才能彻底删除,所以需要有一个数据结构专门存储未确认的消息
    //为了方便找到未确认的消息并进行删除,使用hash结构,第一个key是queueName,第二个key是messageId
    private ConcurrentHashMap<String,ConcurrentHashMap<String,Message>> queuesMessageWaitAckMap=new ConcurrentHashMap<>();
    //消息中心,用来存放全部的消息,key=messageId
    private ConcurrentHashMap<String,Message> messagesCenter=new ConcurrentHashMap<>();

    //init方法啥也没干,为了方便扩展
    public void init(){}
    //queue的相关操作
    public void insertQueue(QueueEntity queue){
        queuesMap.put(queue.getName(),queue);
        log.info("内存成功插入Queue,queueName="+queue.getName());
    }
    public void deleteQueue(String queueName){
        queuesMap.remove(queueName);
        log.info("内存成功删除Queue,queueName="+queueName);
    }
    public QueueEntity getQueue(String queueName){
        return queuesMap.get(queueName);
    }
    //Exchange的相关操作
    public void insertExchange(Exchange exchange){
        exchangesMap.put(exchange.getName(),exchange);
        log.info("内存成功添加Exchange,exchangeName="+exchange.getName());
    }
    public void deleteExchange(String exchangeName){
        exchangesMap.remove(exchangeName);
        log.info("内存成功删除Exchange,exchangeName="+exchangeName);
    }
    public Exchange getExchange(String exchangeName){
        return exchangesMap.get(exchangeName);
    }
    //Binding的相关操作
    public void insertBinding(Binding binding) throws MqException {
        //先找到交换机的所有绑定的hash表
        //如果没有交换机没有绑定,创建一个
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.computeIfAbsent(binding.getExchangeName(),c->new ConcurrentHashMap<>());
        //查找这个绑定是否存在,如果存在,不能插入该绑定,因为如果是多线程插入绑定并且bindingKey不一样,就会覆盖
        //因为既涉及查询又涉及写操作,要加锁变成操作
        synchronized (bindingMap){
            if(bindingMap.get(binding.getQueueName())!=null){
                throw new MqException("[MemoryManager] 要插入的绑定已经存在!,binding="+binding);
            }
            //插入该绑定
            bindingMap.put(binding.getQueueName(),binding);
            log.info("内存插入绑定,binding="+binding);
        }
    }
    //一般情况下,多线程操作,多删一次没啥副作用,所以删除不加锁
    //但是如果删除失败,需要打印一下
    public void deleteBinding(Binding binding){
        //先查找交换机的所有绑定
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.get(binding.getExchangeName());
        if(bindingMap==null){
            log.info("内存删除绑定失败!该交换机没有绑定队列,exchangeName="+binding.getExchangeName());
            return;
        }
        //找到这个绑定并删除
        Binding toDelete=bindingMap.remove(binding.getQueueName());
        if(toDelete==null){
            log.info("内存删除绑定失败!没有找到该绑定,binding="+binding);
            return;
        }
        log.info("内存成功删除绑定,binding="+binding);
    }
    public Binding getBinding(String queueName,String exchangeName){
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.get(exchangeName);
        if(bindingMap==null){
            return null;
        }
        return bindingMap.get(queueName);
    }
    //message的操作
    public void insertMessage(Message message){
        messagesCenter.put(message.getMessageId(),message);
    }
    public void deleteMessage(String messageId){
        messagesCenter.remove(messageId);
    }
    public Message getMessage(String messageId){
        return messagesCenter.get(messageId);
    }
    //消息和队列
    public void sendMessageToQueue(String queueName,Message message){
        //找到给队列存储消息的hash表,不存在则创建
        LinkedList<Message> queueMessages=queueMessagesMap.computeIfAbsent(queueName,c->new LinkedList<>());
        //给这个消息表中插入一条消息
        synchronized (queueMessages){
            queueMessages.add(message);
        }
        //消息中心也要保存一份
        messagesCenter.put(message.getMessageId(),message);
        log.info("成功向队列发送消息并保存到消息中心,queueName="+queueName+",messageId="+message.getMessageId());
    }

    /**
     * 队列向消费者发送消息,同时从队列中删除这条消息,并加入到自己的未确认消息队列中
     */
    public Message getMessageFromQueue(String queueName){
        LinkedList<Message> queueMessages=queueMessagesMap.get(queueName);
        if(queueMessages==null){
            return null;
        }
        Message message=null;
        synchronized (queueMessages){
            if(queueMessages.size()==0){
                return null;
            }
            message=queueMessages.pop();
            log.info("已从队列中取出第一条消息,queueName="+queueName+",messageId="+message.getMessageId());
            return message;
        }
    }
    /**
     * 添加一条未确认消息
     */
    public void insertMessageWaitAck(String queueName,Message message){
        ConcurrentHashMap<String,Message> queueMessageWaitAckMap=queuesMessageWaitAckMap.computeIfAbsent(queueName,c->new ConcurrentHashMap<>());
        queueMessageWaitAckMap.put(message.getMessageId(),message);
        log.info("消息进入待确认队列,queueName="+queueName+",messageId="+message.getMessageId());
    }
    /**
     * 从待确认队列中删除一条消息
     */
    public void deleteMessageWaitAck(String queueName,String messageId) {
        ConcurrentHashMap<String, Message> queueMessageWaitAckMap = queuesMessageWaitAckMap.get(queueName);
        if (queueMessageWaitAckMap == null) {
            return;
        }
        queueMessageWaitAckMap.remove(messageId);
        log.info("将消息从待确认队列中移除,queueName="+queueName+",messageId="+messageId);
    }
    /**
     * 查询未确认消息
     */
    public Message getMessageWaitAck(String queueName, String messageId){
        ConcurrentHashMap<String,Message> queueMessageWaitAckMap=queuesMessageWaitAckMap.get(queueName);
        if(queueMessageWaitAckMap==null){
            return null;
        }
        return queueMessageWaitAckMap.get(messageId);
    }
    /**
     * 从硬盘上恢复数据
     */
    public void loadDiskData(DiskManager manager) throws IOException, MqException, ClassNotFoundException {
        //恢复meta数据
        List<Exchange> exchanges=manager.selectAllExchanges();
        for(Exchange exchange:exchanges){
            exchangesMap.put(exchange.getName(),exchange);
        }
        List<QueueEntity> queueEntities=manager.selectAllQueues();
        for(QueueEntity queue:queueEntities){
            queuesMap.put(queue.getName(),queue);
        }
        List<Binding> bindings=manager.selectAllBindings();
        for(Binding binding:bindings){
            ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.computeIfAbsent(binding.getExchangeName(),c->new ConcurrentHashMap<>());
            bindingMap.put(binding.getQueueName(),binding);
        }
        //恢复message
        //不需要恢复待确认消息,因为持久化的消息会被重新加载到内存中,待确认消息也在里面,可以让消费者重新取一遍
        for(QueueEntity queue:queueEntities){
            LinkedList<Message> queueMessages=manager.loadAllMessages(queue.getName());
            for(Message message:queueMessages){
                sendMessageToQueue(queue.getName(),message);
            }
        }
        log.info("从硬盘上恢复数据成功!");
    }
    /**
     * 查看某个队列的消息数
     */
    public int getQueueSize(QueueEntity queue){
        synchronized (queue){
            LinkedList<Message> messages=queueMessagesMap.get(queue.getName());
            if(messages==null){
                return 0;
            }
            return messages.size();
        }
    }
}

?3.2 测试MemoryManager类

@SpringBootTest
class MemoryManagerTest {
    private MemoryManager memoryManager=null;
    @BeforeEach
    void setUp() {
        memoryManager=new MemoryManager();
        memoryManager.init();
    }

    @AfterEach
    void tearDown() {
        memoryManager=null;
    }

    private QueueEntity createQueue(String queueName){
        QueueEntity queue=new QueueEntity();
        queue.setName(queueName);
        return queue;
    }
    private Exchange createExchange(String exchangeName){
        Exchange exchange=new Exchange();
        exchange.setName(exchangeName);
        return exchange;
    }
    private Binding createBinding(String queueName,String exchangeName){
        Binding binding=new Binding();
        binding.setExchangeName(exchangeName);
        binding.setQueueName(queueName);
        binding.setBindingKey("bidingKey");
        return binding;
    }
    @Test
    void testQueue() {
        QueueEntity expectedQueue =createQueue("testQueue");
        memoryManager.insertQueue(expectedQueue);

        //因为内存中存放的是引用,直接比较两个引用是否是同一个即可
        QueueEntity actualQueue=memoryManager.getQueue("testQueue");
        Assertions.assertTrue(expectedQueue==actualQueue);


        memoryManager.deleteQueue("testQueue");
        actualQueue=memoryManager.getQueue("testQueue");
        Assertions.assertNull(actualQueue);
    }



    @Test
    void testExchange() {
        Exchange expectedExchange=createExchange("testExchange");
        memoryManager.insertExchange(expectedExchange);

        Exchange actualExchange=memoryManager.getExchange("testExchange");
        Assertions.assertTrue(expectedExchange==actualExchange);

        memoryManager.deleteExchange("testExchange");
        actualExchange=memoryManager.getExchange("testExchange");
        Assertions.assertNull(actualExchange);
    }

    @Test
    void insertBinding() throws MqException {
        Binding expectedBinding=createBinding("testQueue","testExchange");
        memoryManager.insertBinding(expectedBinding);

        Binding actualBinding=memoryManager.getBinding("testQueue","testExchange");
        Assertions.assertTrue(expectedBinding==actualBinding);

        memoryManager.deleteBinding(expectedBinding);
        actualBinding=memoryManager.getBinding("testQueue","testExchange");
        Assertions.assertNull(actualBinding);
    }

    private Message createMessage(String content){
        Message message=Message.createMessageWithId("routingKey",null,content.getBytes());
        return message;
    }
    @Test
    void testMessage() {
        Message expectedMessage=createMessage("hello");
        memoryManager.insertMessage(expectedMessage);

        Message actualMessage=memoryManager.getMessage(expectedMessage.getMessageId());
        Assertions.assertTrue(expectedMessage==actualMessage);

        memoryManager.deleteMessage(expectedMessage.getMessageId());
        actualMessage=memoryManager.getMessage(expectedMessage.getMessageId());
        Assertions.assertNull(actualMessage);
    }


    @Test
    void messageToQueue() {
        Message expectedMessage=createMessage("hello");
        QueueEntity queue=createQueue("testQueue");
        memoryManager.sendMessageToQueue(queue.getName(),expectedMessage);

        Message actualMessage=memoryManager.getMessageFromQueue("testQueue");
        Assertions.assertEquals(expectedMessage,actualMessage);
        int size=memoryManager.getQueueSize(queue);
        Assertions.assertEquals(0,size);
    }



    @Test
    void messageWaitAck() {
        Message expectedMessage=createMessage("hello");
        memoryManager.insertMessageWaitAck("testQueue",expectedMessage);

        Message actualMessage=memoryManager.getMessageWaitAck("testQueue",expectedMessage.getMessageId());
        Assertions.assertTrue(expectedMessage==actualMessage);

        memoryManager.deleteMessageWaitAck("testQueue", expectedMessage.getMessageId());
        actualMessage=memoryManager.getMessageWaitAck("testQueue", expectedMessage.getMessageId());
        Assertions.assertNull(actualMessage);
    }



    @Test
    void loadDiskData() throws IOException, MqException, ClassNotFoundException {
        //先给硬盘添加数据
        DemoApplication.context= SpringApplication.run(DemoApplication.class);
        DiskManager diskManager=new DiskManager();
        diskManager.init();
        Binding binding=createBinding("testQueue","testExchange");
        QueueEntity queue=createQueue("testQueue");
        Exchange exchange=createExchange("testExchange");
        diskManager.insertBinding(binding);
        diskManager.insertExchange(exchange);
        diskManager.insertQueue(queue);
        LinkedList<Message> messages=new LinkedList<>();
        for(int i=0;i<10;i++){
            Message message=createMessage("hello"+i);
            messages.add(message);
            diskManager.sendMessage(queue,message);
        }
        for(int i=5;i<10;i++){
            diskManager.deleteMessage(queue,messages.get(i));
        }
        //从硬盘上恢复数据
        memoryManager.loadDiskData(diskManager);
        Binding binding1=memoryManager.getBinding("testQueue","testExchange");
        //因为这个对象是从硬盘上读出来的,所以引用指向的不是同一个对象
        Assertions.assertEquals(binding.getBindingKey(),binding1.getBindingKey());
        Assertions.assertEquals(binding.getQueueName(),binding1.getQueueName());
        Assertions.assertEquals(binding.getExchangeName(),binding1.getExchangeName());

        Exchange exchange1=memoryManager.getExchange("testExchange");
        Assertions.assertEquals(exchange.getType(),exchange1.getType());
        Assertions.assertEquals(exchange.getArguments(),exchange1.getArguments());
        Assertions.assertEquals(exchange.isDurable(),exchange1.isDurable());
        Assertions.assertEquals(exchange.isAutoDelete(),exchange1.isAutoDelete());
        Assertions.assertEquals(exchange.getName(),exchange1.getName());

        QueueEntity queue1=memoryManager.getQueue("testQueue");
        Assertions.assertEquals(queue.getName(),queue1.getName());
        Assertions.assertEquals(queue.getArguments(),queue1.getArguments());
        Assertions.assertEquals(queue.isExclusive(),queue1.isExclusive());
        Assertions.assertEquals(queue.isAutoDelete(),queue1.isAutoDelete());
        Assertions.assertEquals(queue.isDurable(),queue1.isDurable());

        int size=memoryManager.getQueueSize(queue1);
        Assertions.assertEquals(5,size);
        Message message=memoryManager.getMessageFromQueue(queue1.getName());
        Assertions.assertArrayEquals("hello0".getBytes(),message.getBody());
        //删除硬盘上的数据
        diskManager.deleteQueue(queue.getName());
        DemoApplication.context.close();
        File file=new File("./data/meta.db");
        file.delete();
    }
}

四. 实现Virtual Host

虚拟主机,是一个逻辑上的集合,里面包含交换机,绑定,队列和消息.?

有没有童靴发现,我们写的代码里,除了EOFException(文件读到结尾是抛出的异常,属于正常读取文件产生的异常),其他的异常我们都是直接抛出去,交给上层调用者解决.这个上层调用者就是Virtual Host,它负责提供9个API,同时要解决所有可能出现的异常.

• exchangeDeclare: 声明一个交换机,有则不创建,没有则创建
• exchangeDelete: 删除一个交换机
• queueDeclare: 声明一个队列,有则不创建,没有则创建
• queueDelete: 删除一个队列
• queueBind: 创建绑定
• queueUnbind: 解除绑定
• basicPublish: 生产者发布一个消息
• basicConsume: 消费者订阅一个队列,后续该队列收到消息时会将消息推送给这个消费者
• basicAck: 消费者处理完消息后,手动应答该消息

4.1 VirtualHost的实现

下面是VH的代码

@Data
@Slf4j
public class VirtualHost {
    //管理硬盘数据
    private DiskManager diskManager=new DiskManager();
    //管理内存数据
    private MemoryManager memoryManager=new MemoryManager();
    //虚拟主机的唯一标识
    private String virtualHost;
    //多线程涉及到加锁操作
    private Object exchangeLocker=new Object();
    private Object queueLocker=new Object();
    //Router类负责检查routingKey和bindingKey
    private Router router=new Router();
    public VirtualHost(){
        //初始化硬盘数据
        diskManager.init();
        //初始化内存数据
        memoryManager.init();
        //将硬盘数据加载到内存里
        try {
            memoryManager.loadDiskData(diskManager);
        } catch (Exception e) {
            log.info("内存恢复数据失败!");
            e.printStackTrace();
        }
    }

    //没有则创建,有则不创建
    public boolean exchangeDeclare(String exchangeName, ExchangeType type, boolean durable, boolean autoDelete, Map<String,Object> arguments){
        //虚拟主机和交换机之间是1:n的关系,需要在exchangeName前面加上虚拟主机标识
        exchangeName=virtualHost+exchangeName;
        synchronized (exchangeLocker){
            try{
                if(memoryManager.getExchange(exchangeName)!=null){
                    //有这个交换机,直接返回true
                    log.info("要创建的交换机已经存在,exchangeName="+exchangeName);
                    return true;
                }
                Exchange exchange=new Exchange();
                exchange.setName(exchangeName);
                exchange.setDurable(durable);
                exchange.setType(type);
                exchange.setAutoDelete(autoDelete);
                exchange.setArguments(arguments);
                if(durable){
                    //将这个交换机持久化
                    diskManager.insertExchange(exchange);
                }
                memoryManager.insertExchange(exchange);
                log.info("创建交换机完成.exchangeName="+exchangeName);
                return true;
            }catch (Exception e){
                log.info("创建交换机失败.exchangeName="+exchangeName);
                e.printStackTrace();
                return false;
            }
        }
    }

    //删除操作,同样不加锁,因为多删一次没啥副作用
    public boolean exchangeDelete(String exchangeName){
        exchangeName=virtualHost+exchangeName;
        try{
            Exchange exchange=memoryManager.getExchange(exchangeName);
            if(exchange==null){
                //说明要删除的交换机不存在,打印一下日志
                log.info("要删除的交换机不存在,exchangeName="+exchangeName);
                return false;
            }
            if(exchange.isDurable()){
                //硬盘上删除该交换机
                diskManager.deleteExchange(exchangeName);
            }
            memoryManager.deleteExchange(exchangeName);
            log.info("删除交换机成功,exchangeName="+exchangeName);
            return true;
        }catch (Exception e){
            log.info("删除交换机失败,exchangeName="+exchangeName);
            e.printStackTrace();
            return false;
        }
    }

    public boolean queueDeclare(String queueName,boolean durable,boolean autoDelete,boolean exclusive,Map<String,Object> arguments){
        queueName=virtualHost+queueName;
        synchronized (queueLocker){
            try{
                if(memoryManager.getQueue(queueName)!=null){
                    log.info("要创建的队列已存在");
                    return true;
                }
                QueueEntity queue=new QueueEntity();
                queue.setName(queueName);
                queue.setDurable(durable);
                queue.setAutoDelete(autoDelete);
                queue.setExclusive(exclusive);
                queue.setArguments(arguments);

                //先进行硬盘操作,硬盘操作更有可能抛异常
                //如果先进行内存操作,但是硬盘操作抛异常,还要进行数据恢复
                if(durable){
                    diskManager.insertQueue(queue);
                }
                memoryManager.insertQueue(queue);
                log.info("创建队列成功,queueName="+queueName);
                return true;
            } catch (Exception e) {
                log.info("创建队列失败,queueName="+queueName);
                e.printStackTrace();
                return false;
            }
        }
    }
    public boolean queueDelete(String queueName){
        queueName=virtualHost+queueName;
        try{
            QueueEntity queue=memoryManager.getQueue(queueName);
            if(queue==null){
                log.info("要删除的队列不存在,queueName="+queueName);
                return false;
            }
            if(queue.isDurable()){
                diskManager.deleteQueue(queueName);
            }
            memoryManager.deleteQueue(queueName);
            log.info("删除队列成功,queueName="+queueName);
            return true;
        }catch (Exception e){
            log.info("删除队列失败,queueName="+queueName);
            e.printStackTrace();
            return false;
        }
    }
    public boolean queueBind(String queueName,String exchangeName,String bindingKey){
        queueName=virtualHost+queueName;
        exchangeName=virtualHost+exchangeName;
        synchronized (exchangeLocker){
            synchronized (queueLocker){
                try{
                    if(memoryManager.getBinding(queueName,exchangeName)!=null){
                        //这个绑定已经存在,不允许
                        throw new MqException("要创建的绑定已经存在,exchangeName="+exchangeName+",queueName="+queueName);
                    }
                    if(!router.checkBindingKey(bindingKey)){
                        throw new MqException("创建绑定失败,bindingKey非法,bindingKey="+bindingKey);
                    }
                    Binding binding=new Binding();
                    binding.setQueueName(queueName);
                    binding.setExchangeName(exchangeName);
                    binding.setBindingKey(bindingKey);
                    //交换机和队列都持久化时,绑定自然就持久化了
                    Exchange exchange=memoryManager.getExchange(exchangeName);
                    if(exchange==null){
                        throw new MqException("创建绑定失败,交换机不存在,exchangeName="+exchangeName);
                    }
                    QueueEntity queue=memoryManager.getQueue(queueName);
                    if(queue==null){
                        throw new MqException("创建绑定失败,队列不存在,queueName="+queueName);
                    }
                    if(exchange.isDurable()&&queue.isDurable()){
                        diskManager.insertBinding(binding);
                    }
                    memoryManager.insertBinding(binding);
                    log.info("创建绑定成功,binding="+binding);
                    return true;
                } catch (Exception e) {
                    log.info("创建绑定失败,exchangeName="+exchangeName+",queueName="+queueName);
                    e.printStackTrace();
                    return false;
                }
            }
        }
    }

    /**
     * 解绑有两种情况: 1. 先删除了交换机和队列,再解除绑定 2.只解除了绑定
     * 为了兼容第一种情况,不需要检验绑定的交换机和队列是否存在
     * @param queueName
     * @param exchangeName
     * @return
     */
    public boolean queueUnbind(String queueName,String exchangeName){
        try{
            Binding binding=memoryManager.getBinding(queueName,exchangeName);
            if(binding==null){
                log.info("解除绑定失败,绑定不存在,exchangeName="+exchangeName+",queueName="+queueName);
                return false;
            }
            //即使绑定没有持久化,进行删除操作也没啥影响,否则还要判断队列和交换机是否持久化
            diskManager.deleteBinding(binding);
            memoryManager.deleteBinding(binding);
            log.info("解除绑定成功,exchangeName"+exchangeName+",queueName="+queueName);
            return true;
        } catch (Exception e) {
            log.info("解除绑定失败,exchangeName="+exchangeName+",queueName="+queueName);
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 生产者调用该方法,指定发布消息到哪个交换机上
     * 1. 找到交换机,判断类型
     * 2. 创建消息,使用工厂方法创建
     * 3. 根据交换机类型和消息的routingKey转发该消息到不同的队列中
     * @return
     */
    public boolean basicPublish(String exchangeName, String routingKey, BasicProperties properties,byte[] body){
        try{
            if(exchangeName==null){
                //表示使用默认交换机
                exchangeName="";
            }else {
                exchangeName=virtualHost+exchangeName;
            }
            Exchange exchange=memoryManager.getExchange(exchangeName);
            if(exchange==null){
                throw new MqException("发布消息失败,指定交换机不存在,exchangeName="+exchangeName);
            }
            Message message=Message.createMessageWithId(routingKey,properties,body);
            //对交换机的类型进行判断,因为直接交换机的转发规则比较简单,放在vh中
            //topic和fanout交换机放在router类中进行转发判断
            if(exchange.getType()==ExchangeType.DIRECT){
                //此时的routingKey就是要转发的队列名字
                String queueName=virtualHost+routingKey;
                QueueEntity queue=memoryManager.getQueue(queueName);
                if(queue==null){
                    throw new MqException("要转发的队列不存在,queueName="+queueName);
                }
                //判断消息是否持久化
                if(message.isDelivery()==0x2){
                    diskManager.sendMessage(queue,message);
                }
                memoryManager.sendMessageToQueue(queueName,message);
            }else{
                //找到交换机绑定的queue
                ConcurrentHashMap<String,Binding> bindingMap=memoryManager.getBindingsMap().get(exchangeName);
                if(bindingMap==null){
                    //这个交换机没有绑定任何队列,不用转发消息,直接返回
                    return true;
                }
                for(Map.Entry<String,Binding> bindingEntry:bindingMap.entrySet()){
                    //得到队列
                    QueueEntity queue=memoryManager.getQueue(bindingEntry.getKey());
                    if(queue==null){
                        //本来要抛异常,但是为了不影响其他队列的转发,这里只打印日志
                        log.info("交换机绑定的队列不存在");
                        continue;
                    }
                    //判断是否转发
                    Binding binding=bindingEntry.getValue();
                    if(router.route(exchange.getType(),message, binding)){
                        //转发该消息
                        //将消息写入硬盘
                        if(message.isDelivery()==0x2){
                            diskManager.sendMessage(queue,message);
                        }
                        //将消息写入内存
                        memoryManager.sendMessageToQueue(queue.getName(),message);
                        //TODO:通知订阅者取消息
                    }
                }
            }
            log.info("成功发布消息,exchangeName="+exchangeName+",messageId="+message.getMessageId());
            return true;
        } catch (Exception e) {
            log.info("发布消息失败,exchangeName="+exchangeName);
            e.printStackTrace();
            return false;
        }
    }
}

下面是Router类的判断方法,用于检查RoutingKey和BindingKey是否合法,以及二者的匹配(这是自己规定的,童靴们也可以创建自己的匹配规则)

@Data
public class Router {
    /**
     * BindingKey格式规定:
     * 1. 由'.'作为各部分的分隔符
     * 2. 各部分可由字母,数字,下划线组成
     * 3. *表示匹配一个部分,#表示匹配0个或多个部分,通配符只能作为单独的一部分
     * 4. *和# , #和#不能相邻
     * @param bindingKey
     * @return
     */
    public boolean checkBindingKey(String bindingKey){
        if(bindingKey==""){
            //如果创建绑定时绑定的交换机是直接交换机,或者交换机是扇出交换机,
            // 用不到bindingKey,会将bindingKey设置成""
            return true;
        }
        char[] chs=bindingKey.toCharArray();
        for(char ch:chs){
            if(ch>='a'&&ch<='z'){
                continue;
            }
            if(ch>='A'&&ch<='Z'){
                continue;
            }
            if(ch>='0'&&ch<='9'){
                continue;
            }
            if(ch=='.'||ch=='_'||ch=='*'||ch=='#'){
                continue;
            }
            return false;
        }
        //通配符只能作为一个独立的部分
        String[] strs=bindingKey.split(".");
        for(String str:strs){
            if(str.length()>1&&(str.contains("*")||str.contains("#"))){
                return false;
            }
        }
        //通配符相邻
        for(int i=0;i<strs.length-1;i++){
            if(strs[i].equals("*")&&strs[i+1].equals("#")){
                return false;
            }
            if(strs[i].equals("#")&&strs[i+1].equals("#")){
                return false;
            }
            if(strs[i].equals("#")&&strs[i+1].equals("*")){
                return false;
            }
        }
        return true;
    }

    /**
     * RoutingKey格式规定;
     * 1. 由'.'作为各部分的分隔符
     * 2. 各部分可由字母,数字,下划线组成
     * @param routingKey
     * @return
     */
    public boolean checkRoutingKey(String routingKey){
        if(routingKey==""){
            //如果使用的是扇出交换机,这个消息会被转发到该交换机绑定的全部队列上,用不到routingKey
            return true;
        }
        char[] chs=routingKey.toCharArray();
        for(char ch:chs){
            if(ch>='a'&&ch<='z'){
                continue;
            }
            if(ch>='A'&&ch<='Z'){
                continue;
            }
            if (ch=='.'||ch=='_'){
                continue;
            }
            if(ch>='0'&&ch<='9'){
                continue;
            }
            return false;
        }
        return true;
    }

    public boolean route(ExchangeType type, Message message, Binding binding) throws MqException {
        if(type==ExchangeType.FANOUT){
            //与该交换机绑定的全部队列都要存放该消息
            return true;
        }else if(type==ExchangeType.TOPIC){
            return topicRoute(message,binding);
        }else {
            //属于异常情况
            throw new MqException("交换机类型非法!exchangeType="+type);
        }
    }

    private boolean topicRoute(Message message, Binding binding) {
        String routingKey= message.getRoutingKey();
        String bindingKey= binding.getBindingKey();
        int routIndex=0;
        int bindIndex=0;
        String[] routKeys=routingKey.split("\\.");
        String[] bindKeys=bindingKey.split("\\.");
        while (routIndex<routKeys.length&&bindIndex<bindKeys.length){
            //System.out.println("routing[key]="+routKeys[routIndex]+",binding[key]="+bindingKey);
            //有通配符的情况
            if(bindKeys[bindIndex].equals("*")){

                bindIndex++;
                routIndex++;
            } else if(bindKeys[bindIndex].equals("#")){
                bindIndex++;
                if(bindIndex==bindKeys.length){
                    //表明#匹配的是后面的全部
                    return true;
                }
                routIndex=getRoutIndex(routIndex,routKeys,bindKeys[bindIndex]);
                if(routIndex==-1){
                    return false;
                }
                bindIndex++;
                routIndex++;
            }else{
                //普通字符串匹配
                if(!routKeys[routIndex].equals(bindKeys[bindIndex])){
                    return false;
                }
                bindIndex++;
                routIndex++;
            }


        }
        //任何一个索引没有到达终点
        if(bindIndex<bindKeys.length||routIndex<routKeys.length){
            return false;
        }
        //System.out.println("routKey="+routingKey+",bindingKey="+bindingKey);
        return true;
    }

    private int getRoutIndex(int routIndex, String[] routKeys, String bindKey) {
        for(int i=routIndex;i<routKeys.length;i++){
            if(routKeys[i].equals(bindKey)){
                return i;
            }
        }
        return -1;
    }


}

?4.2 basicConsume方法

上面提供的Virtual Host类的代码中,没有实现basicConsume和basicAck方法,并且basicPublish方法也是不完整的.因为这个方法的实现比较复杂,需要另外创建一些类~~

Consume类,是一个函数式接口,里面是一个回调方法,消费者通过这个方法来处理消息.

/**
 * 一个函数型接口,消费者进行消息处理的逻辑
 */
@FunctionalInterface
public interface Consume {
    /**
     * @param consumerTag 消费者标识
     * @param properties message的基本属性
     * @param body message的主体
     */
    void handleDelivery(String consumerTag, BasicProperties properties,byte[] body)throws IOException, MqException;
}

?Consumer类,表示一个消费者.

/**
 * 表示一个完整的消费者
 */
@Data
public class Consumer {
    //消费者唯一标识
    private String consumerTag;
    //订阅的队列的名字
    private String queueName;
    //是否自动回复
    private boolean autoAck;
    //消费消息的方法
    private Consume consume;
    public Consumer(String consumerTag,String queueName,boolean autoAck,Consume consume){
        this.consumerTag=consumerTag;
        this.queueName=queueName;
        this.autoAck=autoAck;
        this.consume=consume;
    }
}

为了建立消费者和队列之间的订阅关系,我们需要给QueueEntity类增加一个成员变量,用于管理该队列的订阅者.

//管理订阅者
    private LinkedList<Consumer> subscribers=new LinkedList<>();
    //采用轮询的方式向消费者投递消息,因此需要记录每次轮到哪个消费者了
    //涉及到线程安全,使用原子类
    private AtomicInteger consumeToken=new AtomicInteger(0);
    //这个消息被送到哪个订阅者手里
    public Consumer chooseConsumer(){
        synchronized (subscribers){
            if(subscribers.size()==0){
                return null;
            }
            int index=consumeToken.get()% subscribers.size();
            consumeToken.getAndIncrement();
            return subscribers.get(index);
        }
    }
    //添加订阅者
    public void addSubscriber(Consumer consumer){
        synchronized (subscribers){
            subscribers.add(consumer);
        }
    }

虚拟主机需要调用ConsumerManager类的方法,管理消费者和队列之间的关系.

下面我们来分析一下这个类的实现.

那么问题来了--扫描线程怎么知道哪个队列收到了消息呢,需要遍历每个队列对应的存储消息的LinkedList吗?

这样做未免太复杂了,我们可以使用一个tokenQueue阻塞队列,当某个队列收到消息后,它的queueName会被放进阻塞队列中,扫描线程只需要检查阻塞队列中是否有元素即可.(参见下图)

?有了这个逻辑,我们就来实现一下ConsumerManager类.

@Slf4j
public class ConsumerManager {
    //manager类需要执行向队列中添加订阅者,收到Ack后删除消息等操作,因此要有一个vh对象
    private VirtualHost virtualHost;
    //阻塞队列,每当queue收到一个消息后,它的queueName就会被放到阻塞队列中
    private BlockingQueue<String> tokenQueue=new LinkedBlockingQueue<>();
    //线程池,用于执行消费者的回调函数
    private ExecutorService workThreadPool= Executors.newFixedThreadPool(10);
    //扫描线程,用于检查阻塞队列中是否有queueName
    private Thread scannerThread=null;

    public ConsumerManager(VirtualHost virtualHost){
        this.virtualHost=virtualHost;
        scannerThread=new Thread(()->{
            try {
                while(true){
                    //阻塞等待tokenQueue的元素
                    String queueName=tokenQueue.take();
                    //log.info("扫描线程收到消息");
                    //队列收到消息后,将消息发给订阅者
                    QueueEntity queue=virtualHost.getMemoryManager().getQueue(queueName);
                    if(queue==null){
                        //队列不存在
                        throw new MqException("投递消息的队列不存在,queueName="+queueName);
                    }
                    //将消息投递给消费者
                    synchronized (queue){
                        consumeMessage(queue);
                    }
                }
                } catch (Exception e) {
                    e.printStackTrace();
                }
        },"scannerThread");
        //将扫描线程设置为后台进程,服务器终止时线程也随之终止
        scannerThread.setDaemon(true);
        scannerThread.start();
    }

    //添加订阅者
    public void addSubscriber(String queueName, String consumerTag, boolean autoAck, Consume consume) throws MqException {
        QueueEntity queue=virtualHost.getMemoryManager().getQueue(queueName);
        if(queue==null){
            //没有该队列
            throw new MqException("[ConsumerManager] 添加订阅者失败,没有该队列,queueName="+queueName);
        }
        //创建一个消费者
        Consumer consumer=new Consumer(consumerTag,queueName,autoAck,consume);
        synchronized (queue){
            //该队列不能接收其它消息
            //将这个消费者添加到队列的订阅者列表中
            queue.addSubscriber(consumer);
            //如果之前有消息,将积压的消息处理掉
            int n=virtualHost.getMemoryManager().getQueueSize(queue);
            for(int i=0;i<n;i++){
                consumeMessage(queue);
            }
        }

    }

    //因为调用该方法时加锁了,所以这个方法就不加锁了
    private void consumeMessage(QueueEntity queue) {
        //选出一个订阅者
        Consumer luckyDog=queue.chooseConsumer();
        if(luckyDog==null){
            //当前队列没有订阅者,不进行投递
            log.info("当前队列没有订阅者,queueName="+queue.getName());
            return;
        }
        //得到消息
        Message message=virtualHost.getMemoryManager().getMessageFromQueue(queue.getName());
        if(message==null){
            //当前队列没有消息,这属于异常情况,不过问题不大,打印一下日志就行
            log.info("当前队列没有消费者,queueName="+queue.getName());
            return;
        }
        //使用多线程,执行订阅者的消费逻辑
        workThreadPool.submit(()->{
            try {
                //先复制一份保存在未确认序列中
                virtualHost.getMemoryManager().insertMessageWaitAck(queue.getName(),message);
                //消息中心也保存一份
                virtualHost.getMemoryManager().insertMessage(message);
                //执行消费者的消费逻辑
                luckyDog.getConsume().handleDelivery(luckyDog.getConsumerTag(),message.getBasicProperties(),message.getBody() );
                //如果消费者是自动应答,消费完后直接删除该消息的副本
                if(luckyDog.isAutoAck()){
                    if(message.isDelivery()==0x2){
                        //删除硬盘中的数据
                        virtualHost.getDiskManager().deleteMessage(queue,message);
                    }
                    //删除内存中的数据
                    virtualHost.getMemoryManager().deleteMessageWaitAck(queue.getName(), message.getMessageId());
                    virtualHost.getMemoryManager().deleteMessage(message.getMessageId());
                    log.info("收到Ack,删除消息成功,messageId="+message.getMessageId());
                }
                //如果不是,删除的逻辑放在basicAck里执行
            } catch (Exception e) {
                log.info("消费信息失败,consumerTag="+luckyDog.getConsumerTag()+",messageId="+message.getMessageId());
                e.printStackTrace();
            }
        });
    }

    //每次添加一个消息,要通知扫描线程
    public void notifyScanner(String queueName) throws InterruptedException {
        tokenQueue.put(queueName);
    }
}

实现完ConsumerManager类后,我们也就可以补全订阅/发布/确认消息的方法了.虚拟主机要添加一个ConsumerManager成员变量.

下面是这三个方法的实现.

    /**
     * 生产者调用该方法,指定发布消息到哪个交换机上
     * 1. 找到交换机,判断类型
     * 2. 创建消息,使用工厂方法创建
     * 3. 根据交换机类型和消息的routingKey转发该消息到不同的队列中
     * @return
     */
    public boolean basicPublish(String exchangeName, String routingKey, BasicProperties properties,byte[] body){
        try{
            if(exchangeName==null){
                //表示使用默认交换机
                exchangeName="";
            }else {
                exchangeName=virtualHost+exchangeName;
            }
            Exchange exchange=memoryManager.getExchange(exchangeName);
            if(exchange==null){
                throw new MqException("发布消息失败,指定交换机不存在,exchangeName="+exchangeName);
            }
            Message message=Message.createMessageWithId(routingKey,properties,body);
            //对交换机的类型进行判断,因为直接交换机的转发规则比较简单,放在vh中
            //topic和fanout交换机放在router类中进行转发判断
            if(exchange.getType()==ExchangeType.DIRECT){
                //此时的routingKey就是要转发的队列名字
                String queueName=virtualHost+routingKey;
                QueueEntity queue=memoryManager.getQueue(queueName);
                if(queue==null){
                    throw new MqException("要转发的队列不存在,queueName="+queueName);
                }
                //判断消息是否持久化
                if(message.isDelivery()==0x2){
                    diskManager.sendMessage(queue,message);
                }
                memoryManager.sendMessageToQueue(queueName,message);
                //通知订阅者取消息
                consumerManager.notifyScanner(queue.getName());
            }else{
                //找到交换机绑定的queue
                ConcurrentHashMap<String,Binding> bindingMap=memoryManager.getBindingsMap().get(exchangeName);
                if(bindingMap==null){
                    //这个交换机没有绑定任何队列,不用转发消息,直接返回
                    return true;
                }
                for(Map.Entry<String,Binding> bindingEntry:bindingMap.entrySet()){
                    //得到队列
                    QueueEntity queue=memoryManager.getQueue(bindingEntry.getKey());
                    if(queue==null){
                        //本来要抛异常,但是为了不影响其他队列的转发,这里只打印日志
                        log.info("交换机绑定的队列不存在");
                        continue;
                    }
                    //判断是否转发
                    Binding binding=bindingEntry.getValue();
                    if(router.route(exchange.getType(),message, binding)){
                        //转发该消息
                        //将消息写入硬盘
                        if(message.isDelivery()==0x2){
                            diskManager.sendMessage(queue,message);
                        }
                        //将消息写入内存
                        memoryManager.sendMessageToQueue(queue.getName(),message);
                        //通知订阅者取消息
                        consumerManager.notifyScanner(queue.getName());
                    }
                }
            }
            log.info("成功发布消息,exchangeName="+exchangeName+",messageId="+message.getMessageId());
            return true;
        } catch (Exception e) {
            log.info("发布消息失败,exchangeName="+exchangeName);
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 消费者通过该接口订阅一个队列的消息
     */
    public boolean basicConsume(String queueName, String consumerTag, boolean autoAck, Consume consume){
        queueName=virtualHost+queueName;
        try{
            consumerManager.addSubscriber(queueName,consumerTag,autoAck,consume);
            log.info("成功添加订阅者,queueName="+queueName+",consumerTag="+consumerTag);
            return true;
        } catch (Exception e) {
            log.info("添加订阅者失败,queueName="+queueName+",consumerTag="+consumerTag);
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 消费者主动调用该接口,确认某个消息
     */
    public boolean basicAck(String queueName,String messageId){
        queueName=virtualHost+queueName;
        try{
            //找到该队列
            QueueEntity queue=memoryManager.getQueue(queueName);
            if(queue==null){
                throw new MqException("[VirtualHost] 确认消息失败,消息所在的队列不存在,queueName="+queueName);
            }
            //找到这个消息
            Message message=memoryManager.getMessage(messageId);
            if(message==null){
                throw new MqException("[VirtualHost] 确认消息失败,要确认的消息不存在,messageId="+messageId);
            }
            //删除硬盘数据
            if(message.isDelivery()==0x2){
                diskManager.deleteMessage(queue,message);
            }
            //从待确认队列中删除该消息
            memoryManager.deleteMessageWaitAck(queueName,messageId);
            //消息中心删除该消息
            memoryManager.deleteMessage(messageId);
            log.info("收到Ack,删除消息成功,messageId="+messageId);
            return true;
        }catch (Exception e){
            log.info("收到Ack,删除消息失败,messageId="+messageId);
            e.printStackTrace();
            return false;
        }
    }

4.3 测试VirtualHost类

@SpringBootTest
class VirtualHostTest {

    private VirtualHost virtualHost=null;
    @BeforeEach
    void setUp() {
        DemoApplication.context=SpringApplication.run(DemoApplication.class);
        virtualHost=new VirtualHost("default");
    }

    @AfterEach
    void tearDown() {
        virtualHost=null;
        DemoApplication.context.close();
        File file=new File("./data/meta.db");
        file.delete();
    }

    @Test
    void exchangeTest() {
        virtualHost.exchangeDeclare("testExchange", ExchangeType.DIRECT,true,false,null);
        Exchange exchange1=virtualHost.getMemoryManager().getExchange("defaulttestExchange");
        List<Exchange> exchanges=virtualHost.getDiskManager().selectAllExchanges();
        Assertions.assertNotNull(exchange1);
        Assertions.assertEquals(2,exchanges.size());

        virtualHost.exchangeDelete("testExchange");
        exchange1=virtualHost.getMemoryManager().getExchange("testExchange");
        exchanges=virtualHost.getDiskManager().selectAllExchanges();
        Assertions.assertEquals(1,exchanges.size());
        Assertions.assertNull(exchange1);
    }


    @Test
    void queueTest() {
        virtualHost.queueDeclare("testQueue",true,false,false,null);
        QueueEntity queue=virtualHost.getMemoryManager().getQueue(virtualHost.getVirtualHost()+"testQueue");
        List<QueueEntity> queueEntities=virtualHost.getDiskManager().selectAllQueues();
        Assertions.assertNotNull(queue);
        Assertions.assertEquals(1,queueEntities.size());

        virtualHost.queueDelete("testQueue");
        queue=virtualHost.getMemoryManager().getQueue(virtualHost.getVirtualHost()+"testQueue");
        queueEntities=virtualHost.getDiskManager().selectAllQueues();
        Assertions.assertNull(queue);
        Assertions.assertEquals(0,queueEntities.size());
    }



    @Test
    void queueBind() {
        virtualHost.queueDeclare("testQueue",false,false,false,null);
        virtualHost.exchangeDeclare("testExchange",ExchangeType.DIRECT,false,false,null);

        Assertions.assertTrue(virtualHost.queueBind("testQueue","testExchange",""));

    }

    @Test
    void queueUnbind() throws IOException {
        virtualHost.queueDeclare("testQueue",true,false,false,null);
        virtualHost.exchangeDeclare("testExchange",ExchangeType.DIRECT,true,false,null);

        Assertions.assertTrue(virtualHost.queueBind("testQueue","testExchange",""));
        Assertions.assertTrue(virtualHost.queueUnbind("testQueue","testExchange"));
        virtualHost.getDiskManager().deleteQueue("defaulttestQueue");
    }

    @Test
    void directPublish() {
        virtualHost.queueDeclare("testQueue",false,false,false,null);
        //表示交给默认交换机进行转发,RoutingKey就是队列名
        Assertions.assertTrue(virtualHost.basicPublish(null,"testQueue",null,"hello".getBytes()));
        //从队列中取消息
        Message message=virtualHost.getMemoryManager().getMessageFromQueue(virtualHost.getVirtualHost()+"testQueue");
        Assertions.assertArrayEquals("hello".getBytes(),message.getBody());
        Assertions.assertEquals("testQueue",message.getRoutingKey());
    }

    @Test
    void fanoutPublish() throws IOException {
        virtualHost.exchangeDeclare("testExchange",ExchangeType.FANOUT,false,false,null);
        virtualHost.queueDeclare("testQueue1",false,false,false,null);
        virtualHost.queueDeclare("testQueue2",true,false,false,null);

        //建立绑定,因为是fanout交换机,bindingKey没啥用
        Assertions.assertTrue(virtualHost.queueBind("testQueue1","testExchange",""));
        Assertions.assertTrue(virtualHost.queueBind("testQueue2","testExchange",""));
        //向fanout交换机转发消息
        Assertions.assertTrue(virtualHost.basicPublish("testExchange","",null,"hello".getBytes()));
        //看看两个队列上是否都有这条消息
        Message message1=virtualHost.getMemoryManager().getMessageFromQueue(virtualHost.getVirtualHost()+"testQueue1");
        Assertions.assertArrayEquals("hello".getBytes(),message1.getBody());
        Message message2=virtualHost.getMemoryManager().getMessageFromQueue(virtualHost.getVirtualHost()+"testQueue2");
        Assertions.assertArrayEquals("hello".getBytes(),message2.getBody());
        Assertions.assertEquals(message1.getMessageId(),message2.getMessageId());
        virtualHost.getDiskManager().deleteQueue(virtualHost.getVirtualHost()+"testQueue2");
    }

    @Test
    void topicPublish() throws IOException {
        virtualHost.exchangeDeclare("testExchange",ExchangeType.TOPIC,false,false,null);
        virtualHost.queueDeclare("testQueue1",false,false,false,null);
        virtualHost.queueDeclare("testQueue2",false,false,false,null);
        //建立绑定,两个bindingKey和routingKey都匹配
        virtualHost.queueBind("testQueue1","testExchange","aaa.*.ccc");
        virtualHost.queueBind("testQueue2","testExchange","aaa.#");
        //发布消息
        virtualHost.basicPublish("testExchange","aaa.bbb.ccc",null,"hello".getBytes());
        //看看两个队列上是否都有这条消息
        Message message1=virtualHost.getMemoryManager().getMessageFromQueue(virtualHost.getVirtualHost()+"testQueue1");
        Assertions.assertArrayEquals("hello".getBytes(),message1.getBody());
        Message message2=virtualHost.getMemoryManager().getMessageFromQueue(virtualHost.getVirtualHost()+"testQueue2");
        Assertions.assertArrayEquals("hello".getBytes(),message2.getBody());
        Assertions.assertEquals(message1.getMessageId(),message2.getMessageId());
        //virtualHost.getDiskManager().deleteQueue(virtualHost.getVirtualHost()+"testQueue2");
    }
    //先发布再订阅,使用直接交换机,不需要建立绑定了
    @Test
    void basicConsume1() throws InterruptedException {
        virtualHost.exchangeDeclare("testExchange",ExchangeType.DIRECT,false,false,null);
        virtualHost.queueDeclare("testQueue",false,false,false,null);
        //发布消息
        virtualHost.basicPublish("testExchange","testQueue",null,"hello".getBytes());
        Thread.sleep(200);
        //订阅消息,使用自动回复,手动回复下面会进行测试
        virtualHost.basicConsume("testQueue", "testConsumer", true, new Consume() {
            @Override
            public void handleDelivery(String consumerTag, BasicProperties properties, byte[] body) throws IOException, MqException {
                Assertions.assertEquals("testConsumer",consumerTag);
                Assertions.assertArrayEquals("hello".getBytes(),body);
            }
        });

    }
    //先订阅再发布,使用直接交换机,不需要建立绑定了
    @Test
    void basicConsume2() throws InterruptedException {
        virtualHost.exchangeDeclare("testExchange",ExchangeType.DIRECT,false,false,null);
        virtualHost.queueDeclare("testQueue",false,false,false,null);
        //订阅消息,使用自动回复
        virtualHost.basicConsume("testQueue", "testConsumer", true, new Consume() {
            @Override
            public void handleDelivery(String consumerTag, BasicProperties properties, byte[] body) throws IOException, MqException {
                Assertions.assertEquals("testConsumer",consumerTag);
                Assertions.assertArrayEquals("hello".getBytes(),body);
            }
        });
//        Thread.sleep(200);
        //发布消息
        virtualHost.basicPublish("testExchange","testQueue",null,"hello".getBytes());
        //留点时间等待消费者把消息处理掉
        Thread.sleep(500);
    }
    @Test
    void basicAck() throws InterruptedException {
        virtualHost.exchangeDeclare("testExchange",ExchangeType.DIRECT,false,false,null);
        virtualHost.queueDeclare("testQueue",false,false,false,null);
        Message message=new Message();
        virtualHost.basicConsume("testQueue", "testConsumer", false, new Consume() {
            @Override
            public void handleDelivery(String consumerTag, BasicProperties properties, byte[] body) throws IOException, MqException {
                message.setMessageId(properties.getMessageId());
                Assertions.assertEquals("testConsumer",consumerTag);
                Assertions.assertArrayEquals("hello".getBytes(),body);
            }
        });
        virtualHost.basicPublish("testExchange","testQueue",null,"hello".getBytes());
        Thread.sleep(100);
        //消费者手动回复
        Assertions.assertTrue(virtualHost.basicAck("testQueue",message.getMessageId()));
    }
}

五. 实现Broker Server

前文做了那么多的铺垫,我们已经实现了Broker服务器内部的9个核心API,接下来我们就可以实现Broker服务器与客户端的交互了.

回顾一下交互模型.

左边的客户端是生产者,右边的客户端是消费者.它们与服务器之间都需要通过网络进行通信.

这里我们使用自定义的应用层协议,借助TCP协议进行客户端与服务器之间的通信.

客户端需要使用本地的API远程调用服务器的方法,也就是说,服务器提供的API和客户端本地提供的API是相互对应的.除了9个核心API之外,服务器还应该提供一些API.

• 创建channel
• 销毁channel
• 创建交换机
• 销毁交换机
• 创建队列
• 销毁队列
• 创建绑定
• 解除绑定
• 发送消息
• 订阅队列
• 确认消息
• 返回消息,消费者订阅一个队列后,当该队列收到消息时,会主动将消息发给订阅者

5.1 应用层协议的设计

学习网络通信的时候我们就谈到过,应用层协议是由程序猿自己定义的.而我们学过的http/https协议,是一些知名的应用层协议,并且是文本协议.

因为我们传输的消息是二进制的,不方便使用文本协议,我们可以自己定义二进制的应用层协议.

先来定义请求格式.

?下面是响应格式(和请求格式相比,不能说毫不相干,只能说一模一样)

?下面来规定一下type对应的API:

• 0x1,创建channel
• 0x2,关闭channel
• 0x3,创建交换机
• 0x4,销毁交换机
• 0x5,创建队列
• 0x6,销毁队列
• 0x7,创建绑定
• 0x8,解除绑定
• 0x9,发布message
• 0xa,订阅队列
• 0xb,发送ack
• 0xc,服务器返回订阅的消息

因为tcp是以字节为单位进行信息传输的,length部分是为了解决TCP协议的"粘包问题".

针对payLoad部分,如果是一个请求,payLoad里存放了调用方法需要的参数;如果是一个响应,payLoad里存放了方法的返回值.

5.2 请求/响应相关类的创建

首先建立Request和Response类,网络传输的主体就是它们.

/**
 * 因为请求和响应需要在网络上进行传输,需要进行序列化
 * 请求格式: type 4byte,length 4byte,payLoad
 */
@Data
public class Request implements Serializable {
    private int type;
    private int length;
    private byte[] payLoad;
}

/**
 * 响应格式: type 4byte,length 4byte,payLoad
 */
@Data
public class Response implements Serializable {
    private int type;
    private int length;
    private byte[] payLoad;
}

针对payLoad部分,我们需要定义基本格式.

对于请求来说,payLoad部分需要有调用方法所需要的参数,还需要定义一个rid保证保证请求和响应之间的对应关系,同时也需要一个channelId用于标识是哪个通道调用的这个方法.

(先剧透一下,一个客户端和服务器建立连接后,就相当于建立了一个Connection,我们前面谈到过,一个Connection可以包含多个通道,每个通道发送请求后,在收到响应之前是阻塞状态,这个channelId就是用来唤醒阻塞的线程的)

/**
 * 客户端发送请求时,要传的基本参数
 */
@Data
public class BasicArguments implements Serializable {
    //与请求的rid形成对应关系
    private String rid;
    //标识一个通道
    private String channelId;    
}

因为方法的参数不同,要传输的对象也不同,我们需要针对每个方法分别定义参数类.

/**
 * 针对basicPublish方法
 */
@Data
public class BasicPublishArguments extends BasicArguments implements Serializable {
    private String exchangeName;
    private String routingKey;
    private BasicProperties properties;
    private byte[] body;
}
/**
 * 针对basicConsume方法
 */
@Data
public class BasicConsumeArguments extends BasicArguments implements Serializable {
    private String queueName;
    private String consumerTag;
    private boolean autoAck;
    //basicConsume方法还有一个参数是回调函数,没有办法通过网络传输
    //对于Broker Server来说,它处理消息的逻辑就是将消息发送给客户端
}
/**
 * 对应exchangeDeclare方法
 */
@Data
public class ExchangeDeclareArguments extends BasicArguments implements Serializable {
    private String exchangeName;
    private ExchangeType type;
    private boolean durable;
    private boolean autoDelete;
    private Map<String, Object> arguments;
}
/**
 * 对应exchangeDelete方法
 */
@Data
public class ExchangeDeleteArguments extends BasicArguments implements Serializable {
    private String exchangeName;
}
/**
 * 针对queueBind方法
 */
@Data
public class QueueBindArguments extends BasicArguments implements Serializable {
    private String queueName;
    private String exchangeName;
    private String bindingKey;
}
/**
 * 对应queueDeclare方法
 */
@Data
public class QueueDeclareArguments extends BasicArguments implements Serializable {
    private String queueName;
    private boolean durable;
    private boolean autoDelete;
    private boolean exclusive;
    private Map<String,Object> arguments;
}
/**
 * 针对queueDelete方法
 */
@Data
public class QueueDeleteArguments extends BasicArguments implements Serializable {
    private String queueName;
}
/**
 * 针对queueUnbind方法
 */
@Data
public class QueueUnbindArguments extends BasicArguments implements Serializable {
    private String queueName;
    private String exchangeName;
}
/**
 * 针对basicAck方法
 */
@Data
public class BasicAckArguments extends BasicArguments implements Serializable {
    private String queueName;
    private String messageId;
}

/**
 * 响应的基本格式
 */
@Data
public class BasicReturns implements Serializable {
    private String rid;
    private String channelId;
    //调用9个api的返回值
    private boolean isOk;
}

@Data
public class MessageReturns extends BasicReturns implements Serializable {
    private String consumerTag;
    private BasicProperties properties;
    private byte[] body;
}

@Slf4j
public class BrokerServer {
    //当前只实现一个虚拟主机,后续可自行进行扩展
    private VirtualHost virtualHost=new VirtualHost("default_");
    //key=channelId,value为socket对象,用于表示channel属于哪个TCP连接
    private ConcurrentHashMap<String, Socket> channelsMap=new ConcurrentHashMap<>();
    private ServerSocket serverSocket;
    //给多个客户端提供服务时,需要用到多线程
    private ExecutorService threadPool= Executors.newCachedThreadPool();
    //用于关闭服务器,本来只需要kill掉进程即可,这里是为了方便进行单元测试
    private volatile boolean run=true;

    public BrokerServer(int port) throws IOException {
        serverSocket=new ServerSocket(port);
    }
    public void start(){
        try{
            log.info("Broker Server启动服务!");
            while (run){
                //接收一个请求
                Socket clientSocket=serverSocket.accept();
                //多线程处理请求
                threadPool.submit(()->{
                    processConnection(clientSocket);
                });
            }
        } catch (IOException e) {
            log.info("服务器关闭");
            //e.printStackTrace();
        }
    }

    public void stop() throws IOException {
        run=false;
        //关闭全部线程
        threadPool.shutdownNow();
        //关闭连接
        serverSocket.close();
    }
    private void processConnection(Socket clientSocket) {
        try(InputStream inputStream= clientSocket.getInputStream();
            OutputStream outputStream=clientSocket.getOutputStream()) {
            try (DataInputStream dataInputStream = new DataInputStream(inputStream);
                 DataOutputStream dataOutputStream = new DataOutputStream(outputStream)) {
                //因为采用的是长连接,需要不断的读取请求
                while (true) {
                    //接收请求并解析
                    Request request = readRequest(dataInputStream);
                    //处理请求
                    Response response = processRequest(request, clientSocket);
                    //将响应发送给客户端
                    writeResponse(dataOutputStream, response);
                }
            } catch (EOFException | SocketException e) {
                log.info("信息传输结束,clientSocket=" + clientSocket.getRemoteSocketAddress());
            }
        }catch (IOException | ClassNotFoundException | MqException e) {
                log.info("信息传输异常");
                e.printStackTrace();
        }finally {
            //断开连接
            try {
                clientSocket.close();
                //断开连接之后,这个TCP连接包含的channel应该清除
                clearChannel(clientSocket);
                log.info("与客户端断开连接,clientSocket="+clientSocket.getRemoteSocketAddress());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void clearChannel(Socket clientSocket) {
        LinkedList<String> channels=new LinkedList<>();
        for(Map.Entry<String,Socket> entry: channelsMap.entrySet()){
            if(entry.getValue()==clientSocket){
                //对于集合类,不能一边遍历一边清除元素
                channels.add(entry.getKey());
            }
        }
        for(String channelId:channels){
            channelsMap.remove(channelId);
        }
        log.info("已清理客户端的全部channel,clientSocket="+clientSocket.getRemoteSocketAddress());
    }

    private void writeResponse(DataOutputStream dataOutputStream, Response response) throws IOException {
            dataOutputStream.writeInt(response.getType());
            dataOutputStream.writeInt(response.getLength());
            dataOutputStream.write(response.getPayLoad());
            //刷新缓冲区
            dataOutputStream.flush();
    }

    private Request readRequest(DataInputStream dataInputStream) throws IOException {
        Request request=new Request();
        request.setType(dataInputStream.readInt());
        int expectedLength=dataInputStream.readInt();
        byte[] payLoad=new byte[expectedLength];
        int actualLength=dataInputStream.read(payLoad);
        if(expectedLength!=actualLength){
            throw new IOException("[BrokerServer] 请求的格式不正确!expectedLength="+expectedLength+",actualLength="+actualLength);
        }
        request.setLength(actualLength);
        request.setPayLoad(payLoad);
        return request;
    }

    private Response processRequest(Request request, Socket clientSocket) throws MqException, IOException, ClassNotFoundException {
        BasicArguments basicArguments= (BasicArguments) BinaryTool.fromBytes(request.getPayLoad());
        //log.info("收到的arguments="+basicArguments);
        boolean ok=true;
        //分析响应类型
        switch (request.getType()){
            case 0x1:{
                //创建channel
                String channelId=basicArguments.getChannelId();
                channelsMap.put(channelId,clientSocket);
                log.info("成功创建channel");
                break;
            }
            case 0x2:{
                //销毁channel
                String channelId= basicArguments.getChannelId();
                channelsMap.remove(channelId);
                log.info("销毁channel成功");
                break;
            }
            case 0x3:{
                //创建交换机
                //先转换成API需要的参数对象
                ExchangeDeclareArguments arguments=(ExchangeDeclareArguments) basicArguments;
                ok=virtualHost.exchangeDeclare(arguments.getExchangeName(), arguments.getType(), arguments.isDurable(), arguments.isAutoDelete(),arguments.getArguments());
                break;
            }
            case 0x4:{
                //销毁交换机
                ExchangeDeleteArguments arguments=(ExchangeDeleteArguments) basicArguments;
                ok= virtualHost.exchangeDelete(arguments.getExchangeName());
                break;
            }
            case 0x5:{
                //创建队列
                QueueDeclareArguments arguments=(QueueDeclareArguments) basicArguments;
                ok= virtualHost.queueDeclare(arguments.getQueueName(), arguments.isDurable(), arguments.isAutoDelete(), arguments.isExclusive(),arguments.getArguments());
                break;
            }
            case 0x6:{
                //销毁队列
                QueueDeleteArguments arguments=(QueueDeleteArguments) basicArguments;
                ok= virtualHost.queueDelete(arguments.getQueueName());
                break;
            }
            case 0x7:{
                //创建绑定
                QueueBindArguments arguments=(QueueBindArguments) basicArguments;
                ok= virtualHost.queueBind(arguments.getQueueName(), arguments.getExchangeName(), arguments.getBindingKey());
                break;
            }
            case 0x8:{
                //解除绑定
                QueueUnbindArguments arguments=(QueueUnbindArguments) basicArguments;
                ok= virtualHost.queueUnbind(arguments.getQueueName(), arguments.getExchangeName());
                break;
            }
            case 0x9:{
                //发布消息
                BasicPublishArguments arguments=(BasicPublishArguments) basicArguments;
                ok= virtualHost.basicPublish(arguments.getExchangeName(), arguments.getRoutingKey(), arguments.getProperties(), arguments.getBody());
                //log.info("消息内容,body="+new String(arguments.getBody()));
                break;
            }
            case 0xa:{
                //订阅队列
                BasicConsumeArguments arguments=(BasicConsumeArguments) basicArguments;
                ok= virtualHost.basicConsume(arguments.getQueueName(), arguments.getConsumerTag(), arguments.isAutoAck(), new Consume() {
                    //这个回调函数负责将收到的消息发送给客户端
                    @Override
                    public void handleDelivery(String consumerTag, BasicProperties properties, byte[] body) throws IOException, MqException {
                        //先找到要发给哪个客户端,consumerTag实际上就是channelId
                        Socket luckyDogSocket=channelsMap.get(consumerTag);
                        if(luckyDogSocket==null||luckyDogSocket.isClosed()){
                            //说明服务器和客户端的连接断开,属于异常情况
                            throw new MqException("[BrokerServer] 客户端与服务器连接异常,clientSocket="+luckyDogSocket.getRemoteSocketAddress());
                        }
                        //构造MessageReturns对象
                        MessageReturns messageReturns=new MessageReturns();
                        //因为这个响应是由服务器主动发起的,没有对应的rid
                        messageReturns.setConsumerTag(consumerTag);
                        messageReturns.setChannelId(consumerTag);
                        //messageReturns.setRid("");
                        messageReturns.setProperties(properties);
                        messageReturns.setBody(body);
                        //将这个对象变成字节数组,作为response的载荷
                        byte[] payLoad=BinaryTool.toBytes(messageReturns);
                        //构造一个Response
                        Response response=new Response();
                        response.setType(0x0c);
                        response.setLength(payLoad.length);
                        response.setPayLoad(payLoad);
                        //将响应发送给客户端
                        DataOutputStream outputStream=new DataOutputStream(luckyDogSocket.getOutputStream());
                        synchronized (luckyDogSocket){
                            //多线程发给同一个客户端时message会发生错误
                            writeResponse(outputStream,response);
                        }
                    }
                });
                break;
            }
            case 0xb:{
                //发送ack
                BasicAckArguments arguments=(BasicAckArguments) basicArguments;
                ok=virtualHost.basicAck(arguments.getQueueName(), arguments.getMessageId());
                break;
            }
            default:{
                //异常情况
                throw new MqException("[BrokerServer] 请求类型不正确,requestType="+request.getType());
            }
        }
        //构造一个响应
        //构造一个return对象
        BasicReturns returns=new BasicReturns();
        returns.setOk(ok);
        returns.setChannelId(basicArguments.getChannelId());
        returns.setRid(basicArguments.getRid());
        byte[] payLoad=BinaryTool.toBytes(returns);
        //构造一个响应
        Response response=new Response();
        response.setType(request.getType());
        response.setLength(payLoad.length);
        response.setPayLoad(payLoad);
        log.info("处理得到响应,basicReturns="+returns);
        return response;
    }
}

/**
 * 负责和服务器的通信
 */
@Data
@Slf4j
public class Connection {
    //与服务器建立连接
    private Socket socket;
    //socket的输入流和输出流对象
    private InputStream inputStream;
    private OutputStream outputStream;
    private DataInputStream dataInputStream;
    private DataOutputStream dataOutputStream;
    //记录当前TCP连接都包含了哪些channel,key=channelId
    private ConcurrentHashMap<String,Channel> channelMap=new ConcurrentHashMap<>();
    //使用线程池,进行响应的处理
    private ExecutorService workThreadPool= Executors.newFixedThreadPool(10);

    public Connection(String host, int port) throws IOException {
        socket=new Socket(host,port);
        inputStream=socket.getInputStream();
        outputStream= socket.getOutputStream();
        dataInputStream=new DataInputStream(inputStream);
        dataOutputStream=new DataOutputStream(outputStream);
        //创建一个扫描线程,用于接收响应
        Thread scannerThread=new Thread(()->{
            try {
                while(!socket.isClosed()){
                    Response response=readResponse();
                    //log.info("收到响应,response="+response);
                    processResponse(response);
                }
            } catch (SocketException | EOFException e) {
                log.info("信息传输完毕,连接断开,serverSocket="+socket.getRemoteSocketAddress());
                //e.printStackTrace();
            }catch (Exception e){
                log.info("连接异常,serverSocket="+socket.getRemoteSocketAddress());
                e.printStackTrace();
            }
        },"scannerThreadClient");
        scannerThread.setDaemon(true);
        scannerThread.start();
    }

    private void processResponse(Response response) {
        //因为客户端处理响应比较耗时,采用多线程
        workThreadPool.submit(()->{
            try {
                //解析payLoad
                byte[] payLoad= response.getPayLoad();
                //响应分为两种类型: 1. 请求收到的响应 2. 订阅的消息
                if(response.getType()==0xc){
                    //订阅的消息,没有对应的rid
                    MessageReturns messageReturns=(MessageReturns) BinaryTool.fromBytes(payLoad);
                    //调用channel的handleDelivery方法
                    Channel channel=channelMap.get(messageReturns.getChannelId());
                    if(channel==null){
                        throw new MqException("[Connection] 接收message失败,消息对应的channel不存在,channelId="+messageReturns.getChannelId());
                    }
                    channel.getConsume().handleDelivery(messageReturns.getConsumerTag(), messageReturns.getProperties(), messageReturns.getBody());
                }else{
                    //请求收到对应的响应
                    BasicReturns returns= (BasicReturns) BinaryTool.fromBytes(payLoad);
                    //将return加入到channel的map中
                    String channelId=returns.getChannelId();
                    Channel channel=channelMap.get(channelId);
                    if(channel==null){
                        //通道不存在,抛异常
                        throw new MqException("[Connection] 处理响应失败,响应的通道不存在,channelId="+channelId);
                    }
                    //唤醒等待响应的线程
                    channel.notifyWaitAck(returns);
                }
            } catch (IOException | ClassNotFoundException|MqException e) {
                    log.info("处理响应失败");
                    e.printStackTrace();
            }
        });
    }

    /**
     * 创建一个channel
     * channelId随机生成,以"C-"作为前缀
     */
    public Channel createChannel() throws IOException, InterruptedException {
        String channelId="C-"+ UUID.randomUUID();
        Channel channel=new Channel(channelId,this);
        //将channel添加到本地
        channelMap.put(channelId,channel);
        //服务器那边也要创建channel
        boolean ok=channel.createChannel();
        if(!ok){
            log.info("服务器创建channel失败!");
        }else{
            log.info("创建channel成功!");
        }
        return channel;
    }

    public void deleteChannel(String channelId) throws IOException, InterruptedException {
        //先找到本地的channel
        Channel channel=channelMap.get(channelId);
        if(channel==null){
            log.info("删除channel失败,要删除的channel不存在,channelId="+channelId);
            return;
        }
        //这个channel发送删除请求
        boolean ok=channel.deleteChannel();
        if(ok){
            log.info("服务器删除channel成功");
        }else{
            log.info("服务器删除channel失败");
        }
    }
    /**
     * 读取响应
     */
    public Response readResponse() throws IOException {
        Response response=new Response();
        response.setType(dataInputStream.readInt());
        int expectedLength=dataInputStream.readInt();
        byte[] payLoad=new byte[expectedLength];
        int actualLength=dataInputStream.read(payLoad);
        if(actualLength!=expectedLength){
            throw new IOException("[Connection] 响应的格式不正确,actualLength="+actualLength+",expectedLength="+expectedLength+",type="+response.getType() );
        }
        response.setLength(actualLength);
        response.setPayLoad(payLoad);
        return response;
    }
    /**
     * 输出请求
     */
    public void writeRequest(Request request) throws IOException {
        dataOutputStream.writeInt(request.getType());
        dataOutputStream.writeInt(request.getLength());
        dataOutputStream.write(request.getPayLoad());
        dataOutputStream.flush();
    }

    //断开连接
    public void close() throws IOException {
        //关闭线程池
        workThreadPool.shutdownNow();
        //断开TCP连接
        dataOutputStream.close();
        dataInputStream.close();
        socket.close();
        channelMap=null;
    }
}

@Data
@Slf4j
public class Channel {
    //表示自己是属于哪个连接的
    private Connection connection;
    //唯一标识
    private String channelId;
    //每个channel对应一个消费逻辑
    private Consume consume;
    //每个channel管理自己的rid(发送请求后接收对应的响应)
    //key为rid,value为响应的payLoad
    private ConcurrentHashMap<String, BasicReturns> returnsMap=new ConcurrentHashMap<>();

    public Channel(String channelId,Connection connection){
        this.channelId=channelId;
        this.connection=connection;
    }

    public boolean createChannel() throws IOException, InterruptedException {
        //构造请求参数
        BasicArguments arguments=new BasicArguments();
        arguments.setChannelId(channelId);
        arguments.setRid(generateRid());
        byte[] payLoad= BinaryTool.toBytes(arguments);
        //构造一个请求
        Request request=new Request();
        request.setType(0x1);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        //让connection去发送
        connection.writeRequest(request);
        //等待服务器的响应
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }

    private BasicReturns waitReturns(String rid) throws InterruptedException {
        synchronized (this){
            while (true){
                if(returnsMap.get(rid)==null){
                    wait();
                }
                return returnsMap.get(rid);
            }
        }
    }

    /**
     * 请求的rid随机生成,以"r-"作为前缀
     * @return
     */
    private String generateRid() {
        return "r-"+ UUID.randomUUID();
    }

    public boolean deleteChannel() throws IOException, InterruptedException{
        //构造请求参数
        BasicArguments arguments=new BasicArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x2);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        //发送请求
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }

    public boolean exchangeDeclare(String exchangeName, ExchangeType type, boolean durable, boolean autoDelete, Map<String,Object> argument) throws IOException, InterruptedException {
        //构造请求参数
        ExchangeDeclareArguments arguments=new ExchangeDeclareArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        arguments.setExchangeName(exchangeName);
        arguments.setType(type);
        arguments.setDurable(durable);
        arguments.setAutoDelete(autoDelete);
        arguments.setArguments(argument);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x3);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        //发送请求
        connection.writeRequest(request);
        //等待响应
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean exchangeDelete(String exchangeName) throws IOException, InterruptedException {
        //构造请求参数
        ExchangeDeleteArguments arguments=new ExchangeDeleteArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        arguments.setExchangeName(exchangeName);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x4);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean queueDeclare(String queueName,boolean durable,boolean autoDelete,boolean exclusive,Map<String,Object> argument) throws InterruptedException, IOException {
        QueueDeclareArguments arguments=new QueueDeclareArguments();
        arguments.setChannelId(channelId);
        arguments.setRid(generateRid());
        arguments.setArguments(argument);
        arguments.setAutoDelete(autoDelete);
        arguments.setExclusive(exclusive);
        arguments.setQueueName(queueName);
        arguments.setDurable(durable);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x5);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean queueDelete(String queueName) throws InterruptedException, IOException {
        QueueDeleteArguments arguments=new QueueDeleteArguments();
        arguments.setChannelId(channelId);
        arguments.setRid(generateRid());
        arguments.setQueueName(queueName);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        Request request=new Request();
        request.setType(0x6);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean queueBind(String queueName,String exchangeName,String bindingKey) throws IOException, InterruptedException {
        //构造请求参数
        QueueBindArguments arguments=new QueueBindArguments();
        arguments.setChannelId(channelId);
        arguments.setRid(generateRid());
        arguments.setQueueName(queueName);
        arguments.setExchangeName(exchangeName);
        arguments.setBindingKey(bindingKey);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x7);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        //发送请求
        connection.writeRequest(request);
        //等待响应
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean queueUnbind(String queueName,String exchangeName) throws IOException, InterruptedException {
        //构造请求参数
        QueueUnbindArguments arguments=new QueueUnbindArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        arguments.setQueueName(queueName);
        arguments.setExchangeName(exchangeName);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x8);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        //发送请求
        connection.writeRequest(request);
        //等待响应
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean basicPublish(String exchangeName, String routingKey, BasicProperties properties,byte[] body) throws IOException, InterruptedException {
        //构造请求参数
        BasicPublishArguments arguments=new BasicPublishArguments();
        arguments.setChannelId(channelId);
        arguments.setRid(generateRid());
        arguments.setExchangeName(exchangeName);
        arguments.setRoutingKey(routingKey);
        arguments.setBody(body);
        arguments.setProperties(properties);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0x9);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        connection.writeRequest(request);
        //等待响应
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }

    /**
     * 对应basicConsume方法,本来还应该有一个参数是consumerTag,
     * 但是因为consumerTag==channelId,所以就不作为参数传递了,直接在方法内部赋值
     */
    public boolean basicConsume(String queueName,boolean autoAck,Consume consume) throws InterruptedException, IOException, MqException {
        //一个channel只能有一个回调函数
        if(consume!=null) {
            if (this.consume == null) {
                this.consume = consume;
            } else {
                throw new MqException("[Channel] 该通道已有消费逻辑!,channelId=" + channelId);
            }
        }
        //构造请求参数
        BasicConsumeArguments arguments=new BasicConsumeArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        arguments.setConsumerTag(channelId);
        arguments.setAutoAck(autoAck);
        arguments.setQueueName(queueName);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setType(0xa);
        request.setLength(payLoad.length);
        request.setPayLoad(payLoad);
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }
    public boolean basicAck(String queueName,String messageId) throws IOException, InterruptedException {
        //构造请求参数
        BasicAckArguments arguments=new BasicAckArguments();
        arguments.setRid(generateRid());
        arguments.setChannelId(channelId);
        arguments.setQueueName(queueName);
        arguments.setMessageId(messageId);
        byte[] payLoad=BinaryTool.toBytes(arguments);
        //构造请求
        Request request=new Request();
        request.setPayLoad(payLoad);
        request.setType(0xb);
        request.setLength(payLoad.length);
        connection.writeRequest(request);
        BasicReturns returns=waitReturns(arguments.getRid());
        return returns.isOk();
    }


    /**
     * 因为Connection中使用了线程池来处理每个响应,所以应该唤醒多线程
     * @param returns
     */
    public void notifyWaitAck(BasicReturns returns) {
        synchronized (this){
            returnsMap.put(returns.getRid(),returns);
            notifyAll();
        }
    }
}

@Data
public class ConnectionFactory {
    //指定服务器的Ip和端口
    private String host;
    private int port;
    Connection createConnection() throws IOException {
        return new Connection(host,port);
    }

}

@SpringBootTest
class ConnectionTest {
    private BrokerServer server=null;
    private ConnectionFactory factory=new ConnectionFactory();
    //因为需要同时开启服务器和客户端,用到多线程
    private Thread thread=null;
    @BeforeEach
    void setUp() {
        DemoApplication.context= SpringApplication.run(DemoApplication.class);
        thread=new Thread(()->{
            try {
                server=new BrokerServer(8060);
                server.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        });
        thread.start();
        factory.setHost("127.0.0.1");
        factory.setPort(8060);
    }

    @AfterEach
    void tearDown() throws IOException {
        server.stop();
        DemoApplication.context.close();
        //删文件
        File dataDir=new File("./data");
        for(File file:dataDir.listFiles()){
            if(file.isDirectory()){
                FileUtils.deleteDirectory(file);
            }else if(file.isFile()){
                file.delete();
            }
        }
    }

    @Test
    void createConnection() throws IOException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
    }

    @Test
    void createChannel() throws IOException, InterruptedException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
        Channel channel=connection.createChannel();
        Assertions.assertNotNull(channel);
    }

    @Test
    void deleteChannel() throws IOException, InterruptedException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
        Channel channel=connection.createChannel();
        Assertions.assertNotNull(channel);

        connection.deleteChannel(channel.getChannelId());
        connection.close();
    }

    @Test
    void testQueue() throws IOException, InterruptedException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
        Channel channel=connection.createChannel();
        Assertions.assertNotNull(channel);

        boolean ok1=channel.queueDeclare("testQueue",true,true,false,null);
        boolean ok=channel.queueDelete("testQueue");
        channel.deleteChannel();
        connection.close();
    }

    @Test
    void testExchange() throws IOException, InterruptedException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
        Channel channel=connection.createChannel();
        Assertions.assertNotNull(channel);

        boolean ok=channel.exchangeDeclare("testExchange", ExchangeType.FANOUT,true,false,null);
        Assertions.assertTrue(ok);
        ok=channel.exchangeDelete("testExchange");
        Assertions.assertTrue(ok);
        channel.deleteChannel();
        connection.close();
    }

    @Test
    void testBind() throws IOException, InterruptedException, MqException {
        Connection connection=factory.createConnection();
        Assertions.assertNotNull(connection);
        Channel channel=connection.createChannel();
        Assertions.assertNotNull(channel);

        boolean ok=channel.exchangeDeclare("testExchange", ExchangeType.TOPIC,true,false,null);
        Assertions.assertTrue(ok);
        ok=channel.queueDeclare("testQueue1",true,false,false,null);
        Assertions.assertTrue(ok);
        ok=channel.queueDeclare("testQueue2",true,false,false,null);
        Assertions.assertTrue(ok);
        ok=channel.queueBind("testQueue1","testExchange","#.222");
        Assertions.assertTrue(ok);
        ok=channel.queueBind("testQueue2","testExchange","*.*");
        Assertions.assertTrue(ok);
        ok=channel.basicPublish("testExchange","111.222",null,"hello".getBytes());
        Assertions.assertTrue(ok);
        channel.basicConsume("testQueue1", true, new Consume() {
            @Override
            public void handleDelivery(String consumerTag, BasicProperties properties, byte[] body) throws IOException, MqException {
                Assertions.assertArrayEquals("hello".getBytes(),body);
               // System.out.println(new String(body));
            }
        });
        channel.basicConsume("testQueue2", true, null);
    }
}

@SpringBootApplication
public class DemoApplication {

	public static ConfigurableApplicationContext context;
	public static void main(String[] args) throws IOException {
		context=SpringApplication.run(DemoApplication.class, args);
		BrokerServer server=new BrokerServer(9090);
		server.start();
	}

}

public class DemoConsumer {
    public static void main(String[] args) throws IOException, MqException, InterruptedException, IOException {
        System.out.println("启动消费者!");
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("127.0.0.1");
        factory.setPort(9090);

        Connection connection = factory.createConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare("testExchange", ExchangeType.DIRECT, true, false, null);
        channel.queueDeclare("testQueue", true, false, false, null);

        channel.basicConsume("testQueue", true, new Consume() {
            @Override
            public void handleDelivery(String consumerTag, BasicProperties basicProperties, byte[] body) throws
                    MqException, IOException {
                System.out.println("[消费数据] 开始!");
                System.out.println("consumerTag=" + consumerTag);
                System.out.println("basicProperties=" + basicProperties);
                String bodyString = new String(body, 0, body.length);
                System.out.println("body=" + bodyString);
                System.out.println("[消费数据] 结束!");
            }
        });

        // 由于消费者也不知道生产者要生产多少, 就在这里通过这个循环模拟一直等待消费.
        while (true) {
            Thread.sleep(500);
        }
    }
}

public class DemoProducer {
    public static void main(String[] args) throws IOException, InterruptedException, IOException {
        System.out.println("启动生产者");
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("127.0.0.1");
        factory.setPort(9090);

        Connection connection = factory.createConnection();
        Channel channel = connection.createChannel();

        // 创建交换机和队列
        channel.queueDeclare("testQueue", true, false, false, null);

        // 创建一个消息并发送
        byte[] body = "hello".getBytes();
        //使用默认交换机
        boolean ok = channel.basicPublish("", "testQueue", null, body);
        System.out.println("消息投递完成! ok=" + ok);

        Thread.sleep(500);
        channel.deleteChannel();
        connection.close();
    }
}