HTTPURLConnection.getInputStream（）需要很长时间？

Question

I'm uploading an image file using a HttpURLConnection which takes about 3 seconds for a 5MB file with all the headers, but the moment I open an InputStream with .getInputStream(), the method takes about 8+ seconds to return a stream with. Which is an issue because it seems the upload progress bar gives a bad UX if I have multiple images to upload, they have a considerable pause between each upload, so the progress bar just stops for a couple of seconds between uploads. I've done some googling but no one else seems to have an issue with it?

Normally I would assume the server is slow, but seeing as uploading only takes a couple of seconds, downloading the word 'success' or 'fail' shouldn't really be that much of an issue!

Heres some code! Am I setting anything up wrong initially? Note: This is also within an AsyncTask

    ByteArrayInputStream fileInputStream = null;

    try {
        fileInputStream = new ByteArrayInputStream(dObject.Data);

    } catch (Exception e) {
        e.printStackTrace();
    }


    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    String Tag="3rd";
    try
    {
        //------------------ CLIENT RE QUEST        
        Log.e(Tag,"Inside second Method");      

        // Open a HTTP connection to the URL    
        URL url = new URL(_urlString);
        //connectURL is a URL object
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        // Allow Inputs
        conn.setDoInput(true);

        // Allow Outputs
        conn.setDoOutput(true);

        // Don't use a cached copy.
        conn.setUseCaches(false);

        // Use a post method.
        conn.setRequestMethod("POST");

        conn.setRequestProperty("Connection", "Keep-Alive");

        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);

        DataOutputStream dos = new DataOutputStream( conn.getOutputStream() );

        dos.writeBytes(twoHyphens + boundary + lineEnd);
        //dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + _fileLocation +"\"" + lineEnd);
        dos.writeBytes("Content-Disposition: form-data; name=\"file\";filename=\"" + _fileLocation +"\"" + lineEnd);

        dos.writeBytes(lineEnd);

        Log.e(Tag,"Headers are written");

        // create a buffer of maximum size
        int bytesAvailable = fileInputStream.available();
        int maxBufferSize = 1024;
        int bufferSize = Math.min(bytesAvailable, maxBufferSize);
        byte[] buffer = new byte[bufferSize];



        // read file and write it into form...  
        int bytesRead = fileInputStream.read(buffer, 0, bufferSize);


        while (bytesRead > 0) {
            dos.write(buffer, 0, bufferSize);

            //int value = (int)(((float)((float)totalRead / (float) fileSize)) * 100);

            totalRead += bytesRead;
            //Publish the progress out to be displayed
            publishProgress(totalRead);



            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);


        // close streams
        Log.e(Tag,"File is written");
        fileInputStream.close();
        dos.flush();

        Log.e("TIME", "PRE GETINPUTSTREAM");
        InputStream is = conn.getInputStream(); 
        Log.e("TIME", "POST GETINPUTSTREAM");
        //  retrieve the response from server
        int ch;


        //Build the respose and log
        StringBuilder b =new StringBuilder();
        while( ( ch = is.read() ) != -1 ){
            b.append( (char)ch );
        }
        String s=b.toString();      
        Log.i("Response",s);
        dos.close();

        return;
    }
    catch (MalformedURLException ex)
    {
        ErrorHandler.get().e("3");
    }

    catch (IOException ioe)
    {
        ErrorHandler.get().e("2");
    }

Answer 1

Normally I would assume the server is slow, but seeing as uploading only takes a couple of seconds, downloading the word 'success' or 'fail' shouldn't really be that much of an issue!

I suspect that it really is that the server is slow or overloaded.

• The server could be queueing the HTTP requests and only processing a small number at a time in parallel.

• Or it could have a bottleneck in some database activity that is performed before the response containing the file is written to the response.

• Or it could be generating the file on the fly into an in-memory buffer (slow) and then streaming (fast) from the buffer to the HTTP response.

• Or other explanations like this ...

(It is also theoretically possible that there is something funny going on that slows up the delivery of the request to the server. I would think this was unlikely though.)

---

Have you tried downloading the same file using a web browser? Do you get the same behaviour there?

Answer 2

In my case I found that getInputStream looks slow because this method initialize the ssl handshake (on a https URL call). After the first call, others calls are OK