Hadoop——API操作

代码示例：

package com.atguigu.hdfs;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;

public class HdfsClient {
    private FileSystem fs;
    @Before
    public void  init() throws URISyntaxException, IOException, InterruptedException {
        URI uri=new URI("hdfs://master:9000");
        Configuration configuration=new Configuration();
        String user="root";
        fs=FileSystem.get(uri,configuration,user);
    }
    @After
    public void close() throws IOException {
        // 3 关闭资源
        fs.close();
    }
    //创建目录
    @Test
    public void testmkdir() throws IOException, URISyntaxException, InterruptedException {

        fs.mkdirs(new Path("/homework"));
    }
    //上传
    @Test
    public void testPut() throws IOException {
        //
        fs.copyFromLocalFile(true,true,new Path("D:\\sunwukong.txt"),new Path("/xiyou/huaguoshan"));
    }
    @Test
    public void testListFiles() throws IOException, InterruptedException,
            URISyntaxException {
// 1 获取文件系统
        Configuration configuration = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://master:9000"),
                configuration, "root");
// 2 获取文件详情
        RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(new Path("/"),
                true);
        while (listFiles.hasNext()) {
            LocatedFileStatus fileStatus = listFiles.next();
            System.out.println("========" + fileStatus.getPath() + "=========");
            System.out.println(fileStatus.getPermission());
            System.out.println(fileStatus.getOwner());
            System.out.println(fileStatus.getGroup());
            System.out.println(fileStatus.getLen());
            System.out.println(fileStatus.getModificationTime());
            System.out.println(fileStatus.getReplication());
            System.out.println(fileStatus.getBlockSize());
            System.out.println(fileStatus.getPath().getName());
// 获取块信息
            BlockLocation[] blockLocations = fileStatus.getBlockLocations();
            System.out.println(Arrays.toString(blockLocations));
        }
// 3 关闭资源
        fs.close();
    }

}

运行截图：