hdfs客户端操作

配置HADOOP_HOME环境变量

 

配置Path环境变量。

 

 

在IDEA中创建一个Maven工程HdfsClientDemo，并导入相应的依赖坐标+日志添加

<dependencies>

    <dependency>

        <groupId>org.apache.hadoop</groupId>

        <artifactId>hadoop-client</artifactId>

        <version>3.1.3</version>

    </dependency>

    <dependency>

        <groupId>junit</groupId>

        <artifactId>junit</artifactId>

        <version>4.12</version>

    </dependency>

    <dependency>

        <groupId>org.slf4j</groupId>

        <artifactId>slf4j-log4j12</artifactId>

        <version>1.7.30</version>

    </dependency>

</dependencies>

创建HdfsClient类

public class HdfsClient {

    @Test
    public void testMkdirs() throws IOException, URISyntaxException, InterruptedException {

        // 1 获取文件系统
        Configuration configuration = new Configuration();

        // FileSystem fs = FileSystem.get(new URI("hdfs://hadoop102:8020"), configuration);
        FileSystem fs = FileSystem.get(new URI("hdfs://hadoop102:8020"), configuration,"atguigu");

        // 2 创建目录
        fs.mkdirs(new Path("/xiyou/huaguoshan/"));

        // 3 关闭资源
        fs.close();
    }
}

 HDFS文件上传

public void testCopyFromLocalFile() throws IOException, InterruptedException, URISyntaxException {

    // 1 获取文件系统
    Configuration configuration = new Configuration();
    configuration.set("dfs.replication", "2");
    FileSystem fs = FileSystem.get(new URI("hdfs://hadoop102:8020"), configuration, "atguigu");

    // 2 上传文件
    fs.copyFromLocalFile(new Path("d:/sunwukong.txt"), new Path("/xiyou/huaguoshan"));

    // 3 关闭资源
    fs.close();
｝

HDFS文件下载

public void testCopyToLocalFile() throws IOException, InterruptedException, URISyntaxException{

    // 1 获取文件系统
    Configuration configuration = new Configuration();
    FileSystem fs = FileSystem.get(new URI("hdfs://hadoop102:8020"), configuration, "atguigu");
    
    // 2 执行下载操作
    // boolean delSrc 指是否将原文件删除
    // Path src 指要下载的文件路径
    // Path dst 指将文件下载到的路径
    // boolean useRawLocalFileSystem 是否开启文件校验
    fs.copyToLocalFile(false, new Path("/xiyou/huaguoshan/sunwukong.txt"), new Path("d:/sunwukong2.txt"), true);
    
    // 3 关闭资源
    fs.close();
}

HDFS文件更名和移动

public void testRename() throws IOException, InterruptedException, URISyntaxException{

    // 1 获取文件系统
    Configuration configuration = new Configuration();
    FileSystem fs = FileSystem.get(new URI("hdfs://hadoop102:8020"), configuration, "atguigu"); 
        
    // 2 修改文件名称
    fs.rename(new Path("/xiyou/huaguoshan/sunwukong.txt"), new Path("/xiyou/huaguoshan/meihouwang.txt"));
        
    // 3 关闭资源
    fs.close();
}