如何在Android上从ASP.NET站点下载文件？

public class DownloadTask extends AsyncTask<String, Void, Boolean> {
    protected Boolean doInBackground(String... urls) {
        String fileUrl = urls[0];
        String fileName = urls[1];

        try {
            URL url = new URL(fileUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            InputStream inputStream = connection.getInputStream();
            FileOutputStream outputStream = new FileOutputStream(fileName);

            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }

            outputStream.close();
            inputStream.close();
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

DownloadTask downloadTask = new DownloadTask();
downloadTask.execute("http://example.com/file.pdf", "/sdcard/file.pdf");

<uses-permission android:name="android.permission.INTERNET" />