private void download_cmd()  {
		@SuppressWarnings("resource")
		Scanner sc = new Scanner(System.in);
		System.out.println("Input the filename which you want to download in HDFS:");
		String filename = sc.nextLine();  //ļ
		String data = null;
		try {
			data = client.read(filename);
		} catch (Exception e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		System.out.println(data);
		FileOutputStream fos = null;
		try {
			fos = new FileOutputStream(filename);
			fos.write(data.getBytes()); //ļд뱾
			fos.close();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}