我可以从上一个停止点下载数据吗？

Question

在我的应用程序中，我从远程服务器下载数据。我的数据大小为289 MB。在下载数据时，它会多次发生，下载停止，并从头开始下载。现在我想实现这样一个下载逻辑，它将恢复前一点的数据下载。 HttpURLConnection连接;     class myasyncTask扩展了AsyncTask {

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        lenghtOfFile=0;
        total=0;
        publishProgress(""+0);
        showDialog(prog_bar);
    }

    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        if(pDialog.isShowing()){
            dismissDialog(prog_bar);
        }
        SavePreferences("MEM2", lenghtOfFile);
        if(total==lenghtOfFile){
            Intent i=new Intent(MainActivity.this,audio.class);
            startActivity(i);
        }
        pDialog.setProgress(0);

    }

    @Override
    protected String doInBackground(String... params) {
        // TODO Auto-generated method stub
        try {
            URL url = new URL("");
            connection = (HttpURLConnection) url.openConnection();   
            connection.setRequestMethod("GET");
            connection.setDoOutput(true);
            connection.connect();
            lenghtOfFile= connection.getContentLength();
            FileOutputStream file = new FileOutputStream(new File(Environment.getExternalStorageDirectory()+"/com.test.AndroidApp/" ,"android"));
            InputStream in = connection.getInputStream();
            byte[] data = new byte[1024];
            int count= 0;
            while ((count = in.read(data)) > 0) {
                total += count; //total = total + len1
                publishProgress("" + (int)((total*100)/lenghtOfFile));
                file.write(data, 0,count);
            }
            file.close();
        } catch (Exception e) {
        }
        return null;
    }
    @Override
    protected void onProgressUpdate(String... values) {
        // TODO Auto-generated method stub
        super.onProgressUpdate(values);
        pDialog.setProgress(Integer.parseInt(values[0]));       
        }

}