分布式锁Lock4J 使用总结

Lok4j 简介

lock4j是一个分布式锁组件，其提供了多种不同的支持以满足不同性能和环境的需求。

立志打造一个简单但富有内涵的分布式锁组件。

特点

• 简单易用，功能强大，扩展性强。
• 支持redission,redisTemplate,zookeeper。可混用，支持扩展

Docker 安装Redis

请参考文章：Docker 安装Redis

Docker 安装ZooKeeper

请参考文章:Docker 安装Zookeeper

SpringBoot 集成Lock4j?

Lock4j 之Reids 版本

pom.xml?

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>SpringBootCase</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringBoot-Lock4J</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <mybatisplus-spring-boot-starter.version>3.4.3</mybatisplus-spring-boot-starter.version>
        <mysql-spring-boot-starter.version>8.0.19</mysql-spring-boot-starter.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatisplus-spring-boot-starter.version}</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql-spring-boot-starter.version}</version>
        </dependency>
        <!--添加开源分布式锁Lock4j-->
        <!--若使用redisTemplate作为分布式锁底层，则需要引入-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>lock4j-redis-template-spring-boot-starter</artifactId>
            <version>2.2.4</version>
        </dependency>
    </dependencies>

</project>

application.yml 之Redis 配置

server:
  port: 8086
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://192.168.43.10:3306/bill?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&autoReconnect=true
    username: root
    password: 123456
    hikari:
      minimum-idle: 10
      maximum-pool-size: 20
      idle-timeout: 500000
      max-lifetime: 540000
      connection-timeout: 60000
      connection-test-query: select 1
  redis:
    database: 0
    host: 192.168.43.10
    port: 6379
    jedis:
      pool:
        max-active: 200
        max-wait: -1
        max-idle: 10
        min-idle: 0
    timeout: 6000

mybatis-plus:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: cn.zzg.mybatisplus.entity

controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock.controller;

import com.baomidou.lock.annotation.Lock4j;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/lock4j")
public class Lock4JController {

    @GetMapping("/lockMethod")
    @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000)
    public String lockMethod(@RequestParam String key){
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        return new String(key);
    }

}

Lock4j 之Redission版本

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>SpringBootCase</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringBoot-Lock4JRedission</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--若使用redisson作为分布式锁底层，则需要引入-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>lock4j-redisson-spring-boot-starter</artifactId>
            <version>2.2.4</version>
        </dependency>
    </dependencies>


</project>

application.yml 配置文件

server:
  port: 8089
spring:
  redis:
    database: 0
    host: 192.168.43.10
    port: 6379
    jedis:
      pool:
        max-active: 200
        max-wait: -1
        max-idle: 10
        min-idle: 0
    timeout: 6000

?controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock4j.controller;

import com.baomidou.lock.annotation.Lock4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/lock4j")
public class Lock4JController {

    @GetMapping("/lockMethod")
    @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000)
    public String lockMethod(@RequestParam String key){
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        return new String(key);
    }

}

Lock4j 之ZooKeeper 版本

pom.xml?

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>SpringBootCase</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringBoot-Lock4jZookeeper</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--添加开源分布式锁Lock4j-->
        <!--若使用Zookeeper作为分布式锁底层，则需要引入-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>lock4j-zookeeper-spring-boot-starter</artifactId>
            <version>2.2.4</version>
        </dependency>
    </dependencies>

</project>

application.yml 之zookeeper配置

server:
  port: 8087
spring:
  coordinate:
    zookeeper:
      zkServers: 192.168.43.10:2181

controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock.controller;

import com.baomidou.lock.annotation.Lock4j;
import com.baomidou.lock.executor.ZookeeperLockExecutor;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/lock4j")
public class Lock4JController {

    @GetMapping("/lockMethod")
    @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000, executor = ZookeeperLockExecutor.class)
    public String lockMethod(@RequestParam String key){
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        return new String(key);
    }

}

Lock4J 注解详解

?Lock4J 高级使用

1、配置获取锁超时时间和锁过期时间。

lock4j:
  acquire-timeout: 3000 #默认值3s，可不设置
  expire: 30000 #默认值30s，可不设置
  primary-executor: com.baomidou.lock.executor.RedisTemplateLockExecutor #默认redisson>redisTemplate>zookeeper，可不设置
  lock-key-prefix: lock4j #锁key前缀, 默认值lock4j，可不设置

acquire-timeout /排队时长，超出这个时间退出队列，并抛出超时异常。
expire 锁过期时间 。 主要是防止死锁。默认30秒是为了兼容绝大部分场景。?

2、自定义执行器。

前提条件必须继承抽象类：com.baomidou.lock.executor.AbstractLockExecutor<T>?

ZooKeeper 版本执行器之ZookeeperLockExecutor

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.baomidou.lock.executor;

import java.util.concurrent.TimeUnit;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.imps.CuratorFrameworkState;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZookeeperLockExecutor extends AbstractLockExecutor<InterProcessMutex> {
    private static final Logger log = LoggerFactory.getLogger(ZookeeperLockExecutor.class);
    private final CuratorFramework curatorFramework;

    public InterProcessMutex acquire(String lockKey, String lockValue, long expire, long acquireTimeout) {
        if (!CuratorFrameworkState.STARTED.equals(this.curatorFramework.getState())) {
            log.warn("instance must be started before calling this method");
            return null;
        } else {
            String nodePath = "/curator/lock4j/%s";

            try {
                InterProcessMutex mutex = new InterProcessMutex(this.curatorFramework, String.format(nodePath, lockKey));
                boolean locked = mutex.acquire(acquireTimeout, TimeUnit.MILLISECONDS);
                return (InterProcessMutex)this.obtainLockInstance(locked, mutex);
            } catch (Exception var10) {
                return null;
            }
        }
    }

    public boolean releaseLock(String key, String value, InterProcessMutex lockInstance) {
        try {
            lockInstance.release();
            return true;
        } catch (Exception var5) {
            log.warn("zookeeper lock release error", var5);
            return false;
        }
    }

    public ZookeeperLockExecutor(final CuratorFramework curatorFramework) {
        this.curatorFramework = curatorFramework;
    }
}

Redis 版本执行器之RedisTemplateLockExecutor

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.baomidou.lock.executor;

import java.util.Collections;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;

public class RedisTemplateLockExecutor extends AbstractLockExecutor<String> {
    private static final Logger log = LoggerFactory.getLogger(RedisTemplateLockExecutor.class);
    private static final RedisScript<String> SCRIPT_LOCK = new DefaultRedisScript("return redis.call('set',KEYS[1],ARGV[1],'NX','PX',ARGV[2])", String.class);
    private static final RedisScript<String> SCRIPT_UNLOCK = new DefaultRedisScript("if redis.call('get',KEYS[1]) == ARGV[1] then return tostring(redis.call('del', KEYS[1])==1) else return 'false' end", String.class);
    private static final String LOCK_SUCCESS = "OK";
    private final StringRedisTemplate redisTemplate;

    public String acquire(String lockKey, String lockValue, long expire, long acquireTimeout) {
        String lock = (String)this.redisTemplate.execute(SCRIPT_LOCK, this.redisTemplate.getStringSerializer(), this.redisTemplate.getStringSerializer(), Collections.singletonList(lockKey), new Object[]{lockValue, String.valueOf(expire)});
        boolean locked = "OK".equals(lock);
        return (String)this.obtainLockInstance(locked, lock);
    }

    public boolean releaseLock(String key, String value, String lockInstance) {
        String releaseResult = (String)this.redisTemplate.execute(SCRIPT_UNLOCK, this.redisTemplate.getStringSerializer(), this.redisTemplate.getStringSerializer(), Collections.singletonList(key), new Object[]{value});
        return Boolean.parseBoolean(releaseResult);
    }

    public RedisTemplateLockExecutor(final StringRedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
}

3、自定义Key生成器

前提条件必须实现：com.baomidou.lock.LockKeyBuilder 接口

默认Key生成器：DefaultLockKeyBuilder

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.baomidou.lock;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.context.expression.MethodBasedEvaluationContext;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.expression.BeanResolver;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.StringUtils;

public class DefaultLockKeyBuilder implements LockKeyBuilder {
    private static final ParameterNameDiscoverer NAME_DISCOVERER = new DefaultParameterNameDiscoverer();
    private static final ExpressionParser PARSER = new SpelExpressionParser();
    private BeanResolver beanResolver;

    public DefaultLockKeyBuilder(BeanFactory beanFactory) {
        this.beanResolver = new BeanFactoryResolver(beanFactory);
    }

    public String buildKey(MethodInvocation invocation, String[] definitionKeys) {
        Method method = invocation.getMethod();
        return definitionKeys.length <= 1 && "".equals(definitionKeys[0]) ? "" : this.getSpelDefinitionKey(definitionKeys, method, invocation.getArguments());
    }

    protected String getSpelDefinitionKey(String[] definitionKeys, Method method, Object[] parameterValues) {
        StandardEvaluationContext context = new MethodBasedEvaluationContext((Object)null, method, parameterValues, NAME_DISCOVERER);
        context.setBeanResolver(this.beanResolver);
        List<String> definitionKeyList = new ArrayList(definitionKeys.length);
        String[] var6 = definitionKeys;
        int var7 = definitionKeys.length;

        for(int var8 = 0; var8 < var7; ++var8) {
            String definitionKey = var6[var8];
            if (definitionKey != null && !definitionKey.isEmpty()) {
                String key = (String)PARSER.parseExpression(definitionKey).getValue(context, String.class);
                definitionKeyList.add(key);
            }
        }

        return StringUtils.collectionToDelimitedString(definitionKeyList, ".", "", "");
    }
}

4、自定义锁获取失败策略

前提条件必须实现：com.baomidou.lock.LockFailureStrategy 接口

默认失败策略:DefaultLockFailureStrategy

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.baomidou.lock;

import com.baomidou.lock.exception.LockFailureException;
import java.lang.reflect.Method;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DefaultLockFailureStrategy implements LockFailureStrategy {
    private static final Logger log = LoggerFactory.getLogger(DefaultLockFailureStrategy.class);
    protected static String DEFAULT_MESSAGE = "request failed,please retry it.";

    public DefaultLockFailureStrategy() {
    }

    public void onLockFailure(String key, Method method, Object[] arguments) {
        throw new LockFailureException(DEFAULT_MESSAGE);
    }
}

5、手动获取/释放锁

通用方法：

@Service
public class CommonService {
    @Autowired
    private LockTemplate lockTemplate;

    public void commonLock(String bizId) {
        // 各种查询操作 不上锁
        // ...
        // 获取锁
        final LockInfo lockInfo = lockTemplate.lock(bizId, 30000L, 5000L, RedissonLockExecutor.class);
        if (null == lockInfo) {
            throw new RuntimeException("业务处理中,请稍后再试");
        }
        // 获取锁成功，处理业务
        try {
            System.out.println("执行普通方法 , 当前线程:" + Thread.currentThread().getName());
        } finally {
            //释放锁
            lockTemplate.releaseLock(lockInfo);
        }
        //结束
    }
}

参考资料

官网地址：Lock4J