HDFS IO流操作

一、IO流文件上传

    @Test
    public void testIOPut() throws URISyntaxException, IOException, InterruptedException {
        // 1. 获取对象
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://wt1:9000"), conf, "tom");
        // 2. 获取输入流
        FileInputStream fIS = new FileInputStream(new File("D:\test.txt"));
        // 3. 获取输出流
        FSDataOutputStream fOS = fs.create(new Path("/lili.txt"));
        // 4. 流的对拷
        IOUtils.copyBytes(fIS, fOS, conf);
        // 5. 关闭资源
        IOUtils.closeStream(fOS);
        IOUtils.closeStream(fIS);
        fs.close();
    }

二、IO流文件下载

    @Test
    public void testIODownload() throws URISyntaxException, IOException, InterruptedException {
        // 1. 获取对象
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://wt1:9000"), conf, "tom");
        // 2. 获取输入流
        FSDataInputStream fIS = fs.open(new Path("/abc.txt"));
        // 3. 获取输出流
        FileOutputStream fOI = new FileOutputStream(new File("E:\abc\abc.txt"));
        // 4. 流的对拷
        IOUtils.copyBytes(fIS, fOI, conf);
        // 5. 关闭资源
        IOUtils.closeStream(fOI);
        IOUtils.closeStream(fIS);
        fs.close();
    }

 三、定位读取文件

    // 下载第一块
    @Test
    public void testLocation() throws URISyntaxException, IOException, InterruptedException {
        // 1.获取对象
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://wt1:9000"), conf, "tom");
        // 2.获取输入流
        FSDataInputStream fIS = fs.open(new Path("/jdk-8u261-linux-x64.tar.gz"));
        // 3.获取输出流
        FileOutputStream fOS = new FileOutputStream(new File("E:\abc\jdk-8u261-linux-x64.tar.gz"));
        // 4.流的对拷(只copy128)
        byte[] buf = new byte[1024];
        for (int i = 0; i < 1024 * 128 ; i++) {
            fIS.read(buf);
            fOS.write(buf);
        }
        // 5. 关闭资源
        IOUtils.closeStream(fOS);
        IOUtils.closeStream(fIS);
        fs.close();
    }

    // 下载第二块
    @Test
    public void testDownloadTwo() throws URISyntaxException, IOException, InterruptedException {
        // 1. 获取对象
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://wt1:9000"), conf, "tom");
        // 2. 获取输入流
        FSDataInputStream fIS = fs.open(new Path("/jdk-8u261-linux-x64.tar.gz"));
        // 3. 设置指定读取的起点
        fIS.seek(1024*1024*128);
        // 4. 获取输出流
        FileOutputStream fOS = new FileOutputStream(new File("E:\abc\jdk.tar.gz.part2"));
        // 5. 流的对拷
        IOUtils.copyBytes(fIS, fOS, conf);
        // 6. 关闭连接
        IOUtils.closeStream(fOS);
        IOUtils.closeStream(fIS);
        fs.close();
    }