Java如何基于ProcessBuilder类调用外部程序

@Test
  public void testProcessBuilder() {
    ProcessBuilder processBuilder = new ProcessBuilder();
//    processBuilder.command("ping","127.0.0.1");
    processBuilder.command("ipconfig");
    //将标准输入流和错误输入流合并，通过标准输入流读取信息
    processBuilder.redirectErrorStream(true);
    try {
      //启动进程
      Process start = processBuilder.start();
      //获取输入流
      InputStream inputStream = start.getInputStream();
      //转成字符输入流
      InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "gbk");
      int len = -1;
      char[] c = new char[1024];
      StringBuffer outputString = new StringBuffer();
      //读取进程输入流中的内容
      while ((len = inputStreamReader.read(c)) != -1) {
        String s = new String(c, 0, len);
        outputString.append(s);
        System.out.print(s);
      }
      inputStream.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

 @Test
  public void testFFmpeg() {
    ProcessBuilder processBuilder = new ProcessBuilder();
    //定义命令内容
    List<String> command = new ArrayList<>();
    command.add("D:/program/ffmpeg-20191229-e20c6d9-win64-static/bin/ffmpeg.exe");
    command.add("-i");
    command.add("D:/test/video/1.avi");
    command.add("-y");//覆盖输出文件
    command.add("-c:v");
    command.add("libx264");
    command.add("-s");
    command.add("1280x720");
    command.add("-pix_fmt");
    command.add("yuv420p");
    command.add("-b:a");
    command.add("63k");
    command.add("-b:v");
    command.add("753k");
    command.add("-r");
    command.add("18");
    command.add("D:/test/video/1.mp4");
    processBuilder.command(command);
    //将标准输入流和错误输入流合并，通过标准输入流读取信息
    processBuilder.redirectErrorStream(true);
    try {
      //启动进程
      Process start = processBuilder.start();
      //获取输入流
      InputStream inputStream = start.getInputStream();
      //转成字符输入流
      InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "gbk");
      int len = -1;
      char[] c = new char[1024];
      StringBuffer outputString = new StringBuffer();
      //读取进程输入流中的内容
      while ((len = inputStreamReader.read(c)) != -1) {
        String s = new String(c, 0, len);
        outputString.append(s);
        System.out.print(s);
      }
      inputStream.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }