应用程序被终止或销毁时，java文件下载不完整

Question

当我从服务器下载文件时，如果假设我杀死或销毁了应用程序，则意味着它将只下载一半的数据。如何在应用程序打开时继续下载，或者如何删除文件中不完整的数据

有什么想法吗

private void downloadBookDetails(String pMainFolder, String pFileName, String pDownloadURL) {
    Log.i(TAG, "Coming to this downloadBookDetails ");
    try {
        URL url = new URL(pDownloadURL);
        URLConnection ucon = url.openConnection();
        ucon.setReadTimeout(5000);
        ucon.setConnectTimeout(10000);


        InputStream is = ucon.getInputStream();
        BufferedInputStream inStream = new BufferedInputStream(is, 1024 * 5);

        File directory = new File(pMainFolder, pFileName);
        FileOutputStream outStream = new FileOutputStream(directory);
        byte[] buff = new byte[5 * 1024];

        int len;
        while ((len = inStream.read(buff)) != -1) {
            outStream.write(buff, 0, len);
        }


        outStream.flush();
        outStream.close();
        inStream.close();
    } catch (Exception e) {
        //Add Network Error.
        Log.e(TAG, "Download Error Exception " + e.getMessage());

        e.printStackTrace();
    }
}