Загрузка файла без расширения с сервера

используйте ниже код, он отлично работает для зашифрованных URL-адресов

public class HttpDownloadUtility {
    private static final int BUFFER_SIZE = 4096;

    /**
     * Downloads a file from a URL
     * @param fileURL HTTP URL of the file to be downloaded
     * @param saveDir path of the directory to save the file
     * @throws IOException
     */
    public static void downloadFile(String fileURL, String saveDir)
            throws IOException {
        URL url = new URL(fileURL);
        HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
        int responseCode = httpConn.getResponseCode();

        // always check HTTP response code first
        if (responseCode == HttpURLConnection.HTTP_OK) {
            String fileName = "";
            String disposition = httpConn.getHeaderField("Content-Disposition");
            String contentType = httpConn.getContentType();
            int contentLength = httpConn.getContentLength();

            if (disposition != null) {
                // extracts file name from header field
                int index = disposition.indexOf("filename=");
                if (index > 0) {
                    fileName = disposition.substring(index + 10,
                            disposition.length() - 1);
                }
            } else {
                // extracts file name from URL
                fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1,
                        fileURL.length());
            }

            System.out.println("Content-Type = " + contentType);
            System.out.println("Content-Disposition = " + disposition);
            System.out.println("Content-Length = " + contentLength);
            System.out.println("fileName = " + fileName);

            // opens input stream from the HTTP connection
            InputStream inputStream = httpConn.getInputStream();
            String saveFilePath = saveDir + File.separator + fileName;

            // opens an output stream to save into file
            FileOutputStream outputStream = new FileOutputStream(saveFilePath);

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

            outputStream.close();
            inputStream.close();

            System.out.println("File downloaded");
        } else {
            System.out.println("No file to download. Server replied HTTP code: " + responseCode);
        }
        httpConn.disconnect();
    }
}

url возвращает перенаправление 302 к фактическому .mp3. Браузер делает перенаправление в фоновом режиме для вас, но в вашем приложении вам нужно сделать это самостоятельно. Вот пример того, как это сделать с HttpUrlConnectionhttp://www.mkyong.com/java/java-httpurlconnection-follow-redirect-example/

Если вы заранее знаете тип файла, вы можете загрузить файл с url, который не имеет расширения.

DownloadService .java

public class DownloadService extends IntentService {
    public static final int UPDATE_PROGRESS = 8344;
    private Context context;
    private PowerManager.WakeLock mWakeLock;
    ProgressDialog mProgressDialog;
    String filename;
    File mypath;
    String urlToDownload;
    BroadcastReceiver broadcaster;
    Intent intent1;
    static final public String BROADCAST_ACTION = "com.example.app.activity.test.broadcast";
    public DownloadService() {
        super("DownloadService");   
    }
    @Override
    public void onCreate() {
        // TODO Auto-generated method stub
        super.onCreate();
        intent1 = new Intent(BROADCAST_ACTION);
    }
    @Override
    protected void onHandleIntent(Intent intent) {

        ResultReceiver receiver = (ResultReceiver) intent.getParcelableExtra("receiver");
        try {
            intent1 = new Intent(BROADCAST_ACTION);
            urlToDownload = intent.getStringExtra("url");
            filename= intent.getStringExtra("filename");

            BufferedWriter out;
            try {
                File path=new File("/sdcard/","folder name");
                path.mkdir();
                mypath=new File(path,filename);
                Log.e("mypath",""+mypath);
                if (!mypath.exists()) {
                    out= new BufferedWriter(new FileWriter(mypath));
                    //ut = new OutputStreamWriter(context.openFileOutput( mypath.getAbsolutePath() ,Context.MODE_PRIVATE));
                    out.write("test");
                    out.close();

                } 

            }catch(Exception e){
                e.printStackTrace();
            }
            URL url = new URL(urlToDownload);
            URLConnection connection = url.openConnection();
            connection.connect();
            // this will be useful so that you can show a typical 0-100% progress bar
            int fileLength = connection.getContentLength();

            // download the file
            InputStream input = new BufferedInputStream(connection.getInputStream());
            OutputStream output = new FileOutputStream(mypath);

            byte data[] = new byte[4096];
            long total = 0;
            int count;
            while ((count = input.read(data)) != -1) {
                total += count;
                // publishing the progress....
                Bundle resultData = new Bundle();
                resultData.putInt("progress" ,(int) (total * 100 / fileLength));


                //Log.e("mypath",""+mypath);
                resultData.putString("mypath", ""+mypath);
                receiver.send(UPDATE_PROGRESS, resultData);         

                output.write(data, 0, count);
            }

            output.flush();
            output.close();
            input.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

        Bundle resultData = new Bundle();
        resultData.putInt("progress" ,100);
        resultData.putString("mypath", ""+mypath);
        receiver.send(UPDATE_PROGRESS, resultData);
        intent1.putExtra("progressbar", 100);
        sendBroadcast(intent1);
    }
}

С downloadreceiver.java

public class DownloadReceiver extends ResultReceiver{

    private Context context;
    private PowerManager.WakeLock mWakeLock;
    ProgressDialog mProgressDialog;
    String filename;

    String mypath;
    public DownloadReceiver(Handler handler ,String filename ,Context context) {
        super(handler);

    this.context = context;
        this.filename = filename;

        mProgressDialog = new ProgressDialog(context);
    }

    @Override
    protected void onReceiveResult(int resultCode, Bundle resultData) {
        super.onReceiveResult(resultCode, resultData);
        if (resultCode == DownloadService.UPDATE_PROGRESS) {
            int progress = resultData.getInt("progress");
            mypath = resultData.getString("mypath");
            mProgressDialog.setProgress(progress);
            //Log.e("progress","progress");
            mProgressDialog.setMessage("App name");
            mProgressDialog.setIndeterminate(true);
            mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            mProgressDialog.setCancelable(true);
            if (progress == 100) {
                mProgressDialog.dismiss();

            Log.e("download","download");

            }
        }
    }
}

Теперь запустите службу в вашем mainactivity по приведенному ниже коду:

Intent miIntent = new Intent(mContext, DownloadService.class);
                            miIntent.putExtra("url", url);
                            miIntent.putExtra("filename", id+".mp3");

                            miIntent.putExtra("receiver", new DownloadReceiver(new Handler() , id,mContext));
                            startService(miIntent);