HDFS JAVA API TEST

HDFSTest.java

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

import java.net.URI;
import java.net.URISyntaxException;

/**
 * HDFS Java API Test
 * Created by AhianZhang on 2018/5/17.
 */
public class HDFSTest
{
    FileSystem fileSystem = null;
    Configuration configuration = null;
    public static final String HDFS_PATH = "hdfs://hadoop01:9000";

    @Before
    public void setUp() throws Exception
    {
        configuration = new Configuration();
        fileSystem = FileSystem.get(new URI(HDFS_PATH), configuration,"hadoop01");
        System.out.println("Start");
    }

    /**
     * 创建文件夹
     * @throws Exception
     */
    @Test
    public void mkdir()throws Exception{
        fileSystem.mkdirs(new Path("/JavaApiOpt/test"));
    }

    /**
     * 创建文件
     * @throws Exception
     */
    @Test
    public void creatFile()throws Exception{
     FSDataOutputStream fsDataOutputStream = fileSystem.create(new Path("/JavaApiOpt/test/javaAPITest.log"));
    fsDataOutputStream.write("This is Java Test".getBytes());
    fsDataOutputStream.flush();
    fsDataOutputStream.close();
    }

    /**
     * 查看文件
     * @throws Exception
     */
    @Test
    public void cat()throws Exception{
      FSDataInputStream fsDataInputStream = fileSystem.open(new Path("/JavaApiOpt/test/javaAPITest.log"));
        IOUtils.copyBytes(fsDataInputStream,System.out,1024);
       fsDataInputStream.close();
    }

    /**
     * 重命名
     * @throws Exception
     */
    @Test
    public void rename()throws Exception{
        Path oldPath = new Path("/JavaApiOpt/test/javaAPITest.log");
        Path newPath = new Path("/JavaApiOpt/test/javaAPIRename.log");
        boolean isSuccess = fileSystem.rename(oldPath,newPath);
        System.out.println(isSuccess);
    }

    /**
     * 从本地复制文件到HDFS中
     * @throws Exception
     * 注意：使用 JavaAPI 上传的文件默认采用三个副本策略，而在Hadoop中是一个副本
     */
    @Test
    public void  copyFromLocalFile()throws Exception{
        Path LocalPath = new Path("C:\\Users\\Videos\\Free YouTube Downloader\\gai.mp4");
        Path ToPath = new Path("/JavaApiOpt/test/");

        fileSystem.copyFromLocalFile(LocalPath,ToPath);
    }

    /**
     * 下载
     * @throws Exception
     */
    @Test
    public void  copyToLocal()throws Exception{
        Path ToPath = new Path("D:/gai.mp4");
        Path FromPath = new Path("/JavaApiOpt/test/gai.mp4");

        fileSystem.copyToLocalFile(false,FromPath,ToPath,true);
    }

    /**
     * 列出文件/文件夹
     * @throws Exception
     */
    @Test
    public void listFiles()throws Exception{
      RemoteIterator<LocatedFileStatus> listFiles = fileSystem.listFiles(new Path("/"),true);
        while (listFiles.hasNext()) {

            LocatedFileStatus file = listFiles.next();

            System.out.println(file.getPath().getName());

        }
        System.out.println("=====================================================");
        FileStatus[] status = fileSystem.listStatus(new Path("/"));
        for (FileStatus file : status) {

            System.out.println(file.getPath().getName() + "   " + (file.isDirectory() ? "d" : "f"));

        }
    }

    /**
     * 删除
     * @throws Exception
     */
    @Test
    public void  delete()throws Exception{
        fileSystem.delete(new Path("/JavaApiOpt/test/gai.mp4"),true);
    }
    @After
    public void tearDown() throws Exception
    {
        configuration = null;
        fileSystem = null;
        System.out.println("Close Done");
    }
}