public class MultipartSender extends AsyncTask<Void, Void, Void>
     {
     DataOutputStream dos;
     String lineEnd = "\r\n";
     String boundary =  "*****";
     int bufferSize = 5*1024*1024;
     long fileSize;
     private void writeFilePart(byte[] buffer,int bytesRead,long fragmentCount) throws IOException
         {
         dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"13.3gp("+ fragmentCount +")\"" + lineEnd);
         Log.d(O.TAG,"writeFilePart: фрагмент "+ fragmentCount +" записан");
         dos.writeBytes(lineEnd);
         dos.write(buffer, 0, bytesRead);
         dos.writeBytes(lineEnd);
         dos.writeBytes("--" + boundary + "--" + lineEnd);
         }

     @Override
     protected Void doInBackground(Void... arg)
         {
         Log.d(O.TAG,"doInBackground: поехали");
         HttpURLConnection conn;
         File file= new File("/storage/sdcard1/DCIM/Camera/13.rar");
         Log.d(O.TAG,"doInBackground: file.exist: "+ file.exists() );
         Log.d(O.TAG,"doInBackground: "+ file);
         if( !file.exists() )
             return null;
         int bytesRead;
         byte[] buffer;
         fileSize= file.length();
         String urlString = %ссылка%;
         try
             {
             FileInputStream fileInputStream = new FileInputStream(file);
             URL url = new URL(urlString);
             conn = (HttpURLConnection) url.openConnection();
             conn.setDoInput(true);
             conn.setDoOutput(true);
             conn.setUseCaches(false);
             conn.setRequestMethod("POST");
             conn.setRequestProperty("Connection", "Keep-Alive");
             conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);
             dos = new DataOutputStream( conn.getOutputStream() );
             dos.writeBytes("--" + boundary + lineEnd);
             buffer = new byte[bufferSize];
             long writenFragments=0,progress;
             bytesRead = fileInputStream.read(buffer, 0, bufferSize);
             while (bytesRead > 0)
                 {
                 writenFragments++;
                 writeFilePart(buffer,bytesRead,writenFragments);
                 progress= writenFragments*bufferSize/fileSize;
                 Log.d(O.TAG,"doInBackground: progress: "+ progress +"%");
                 bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                 }
             dos.writeBytes(lineEnd);
             dos.writeBytes("--" + boundary + "--" + lineEnd);
             fileInputStream.close();
             dos.flush();
             dos.close();
             }
         catch (IOException ioe)
             {
              return null;
             }
         try
             {
             Log.d("c123","doInBackground: "+conn.getResponseCode());
             }
         catch (IOException ioex)
             {
             Log.e("Debug", "error: " + ioex.getMessage(), ioex);
             }
         return null;
         }
     }