public void downloadFile1() {
  try{
    //下载路径，如果路径无效了，可换成你的下载路径
    String url = "http://c.qijingonline.com/test.mkv";
    String path = Environment.getExternalStorageDirectory().getAbsolutePath();

    final long startTime = System.currentTimeMillis();
    Log.i("DOWNLOAD","startTime="+startTime);
    //下载函数
    String filename=url.substring(url.lastIndexOf("/") + 1);
    //获取文件名
    URL myURL = new URL(url);
    URLConnection conn = myURL.openConnection();
    conn.connect();
    InputStream is = conn.getInputStream();
    int fileSize = conn.getContentLength();//根据响应获取文件大小
    if (fileSize <= 0) throw new RuntimeException("无法获知文件大小 ");
    if (is == null) throw new RuntimeException("stream is null");
    File file1 = new File(path);
    if(!file1.exists()){
      file1.mkdirs();
    }
    //把数据存入路径+文件名
    FileOutputStream fos = new FileOutputStream(path+"/"+filename);
    byte buf[] = new byte[1024];
    int downLoadFileSize = 0;
    do{
      //循环读取
      int numread = is.read(buf);
      if (numread == -1)
      {
        break;
      }
      fos.write(buf, 0, numread);
      downLoadFileSize += numread;
      //更新进度条
    } while (true);
    Log.i("DOWNLOAD","download success");
    Log.i("DOWNLOAD","totalTime="+ (System.currentTimeMillis() - startTime));
    is.close();
  } catch (Exception ex) {
    Log.e("DOWNLOAD", "error: " + ex.getMessage(), ex);
  }
}

private void downloadFile2(){
  //下载路径，如果路径无效了，可换成你的下载路径
  String url = "http://c.qijingonline.com/test.mkv";
  //创建下载任务,downloadUrl就是下载链接
  DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
  //指定下载路径和下载文件名
  request.setDestinationInExternalPublicDir("", url.substring(url.lastIndexOf("/") + 1));
  //获取下载管理器
  DownloadManager downloadManager= (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
  //将下载任务加入下载队列，否则不会进行下载
  downloadManager.enqueue(request);
}

private void downloadFile3(){
  //下载路径，如果路径无效了，可换成你的下载路径
  final String url = "http://c.qijingonline.com/test.mkv";
  final long startTime = System.currentTimeMillis();
  Log.i("DOWNLOAD","startTime="+startTime);
  Request request = new Request.Builder().url(url).build();
  new OkHttpClient().newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
      // 下载失败
      e.printStackTrace();
      Log.i("DOWNLOAD","download failed");
    }
    @Override
    public void onResponse(Call call, Response response) throws IOException {
      Sink sink = null;
      BufferedSink bufferedSink = null;
      try {
        String mSDCardPath= Environment.getExternalStorageDirectory().getAbsolutePath();
        File dest = new File(mSDCardPath,  url.substring(url.lastIndexOf("/") + 1));
        sink = Okio.sink(dest);
        bufferedSink = Okio.buffer(sink);
        bufferedSink.writeAll(response.body().source());
        bufferedSink.close();
        Log.i("DOWNLOAD","download success");
        Log.i("DOWNLOAD","totalTime="+ (System.currentTimeMillis() - startTime));
      } catch (Exception e) {
        e.printStackTrace();
        Log.i("DOWNLOAD","download failed");
      } finally {
        if(bufferedSink != null){
          bufferedSink.close();
        }
      }
    }
  });
}