java大数据hadoop2.92 Java连接操作

1、要想Java可以连接自己虚拟机的hadoop文件系统，需要给文件系统权限

（1）需要在/usr/local/hadoop/etc/hadoop/core-site.xml

core-site.xml文件配置具体ip

<configuration>
  <property>
    <name>fs.defaultFS</name>
    <value>hdfs://ip:9000</value>
  </property> 
</configuration>

（2）文件权限

hdfs dfs -chmod -R 777 /

2、maven依赖

<!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-common -->
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-hdfs</artifactId>
            <version>2.9.2</version>
        </dependency>

3、具体操作

（1）创建文件夹

Configuration configuration = new Configuration();
configuration.set("fs.defaultFS", "hdfs://ip:9000");
FileSystem fileSystem = FileSystem.get(configuration);
boolean bool = fileSystem.mkdirs(new Path("/test"));
System.out.println(bool);

（2）创建文件

Configuration configuration = new Configuration();
configuration.set("fs.defaultFS", "hdfs://ip:9000");
FileSystem fileSystem = FileSystem.get(configuration);
Path path = new Path("/demo/test1.txt");
FSDataOutputStream out = fileSystem.create(path);
out.write("hfajdhfkafa".getBytes());
out.flush();
out.close();