Question

I’ve written a Servlet that handles file uploads using the Apache commons file upload library. Here is some of the code:

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);

    if (isMultipart) {
        try {
            DiskFileItemFactory fileItemFactory = new DiskFileItemFactory();

            // Set size threshold for storing upload
            fileItemFactory.setSizeThreshold(1 * 1024 * 50); // 50 KB

            // Set temporary directory to store uploaded files above threshold size
            fileItemFactory.setRepository(new File(TEMP_DIRECTORY));

            ServletFileUpload upload = new ServletFileUpload(fileItemFactory);

            //HashMap<String, String> params = new HashMap<String, String>();


            FileItemIterator iterator = upload.getItemIterator(request);
            upload.setSizeMax(REQUEST_MAX_SIZE);

            List items = upload.parseRequest(request);
            Iterator it = items.iterator();

            while (it.hasNext()) {
                FileItem item = (FileItem) it.next();

                if(item.isFormField()) {

                } else {
                    String contentType = item.getContentType();
                    String fileName = item.getName();
                    String fieldName = item.getFieldName();
                    boolean isInMemory = item.isInMemory();
                    long sizeInBytes = item.getSize();
                    File uploadedFile = new File(PATH + "new_audio1.amr");

                    item.write(uploadedFile);

                    System.out.println("Field: " + fieldName);
                    System.out.println("File name: " + fileName);
                    System.out.println("Size: " + sizeInBytes);
                    System.out.println("Is in memory:" + isInMemory);
                }
            }

        } catch (Exception ex) {
            throw new ServletException(ex);
        }
    } else {
        throw new ServletException();
    }

For some reason that escapes me the List ‘items’ is empty so I can’t grab the uploaded file.

For the upload itself, I’ve written some java code:

File audioFile = new File("C:\\Users\\Soto\\Desktop\\test recording.amr");

    String url = "http://localhost:8080/AudioFileUpload/UploadServlet";
    String charset = "UTF-8";

    // random values
    String latitude = "145";
    String longitude = "132";
    String speed = "0";


    String query;
    try {
        query = String.format("latitude=%s&longitude=%s&speed=%s", URLEncoder.encode(latitude, charset), URLEncoder.encode(longitude, charset), URLEncoder.encode(speed, charset));
    } catch (UnsupportedEncodingException e) {
        query = String.format("latitude=%s&longitude=%s&speed=%s", latitude, longitude, speed);
    }

    HttpClient httpClient = new DefaultHttpClient();
    httpClient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);

    HttpPost httpPost = new HttpPost(url + "?" + query);

    MultipartEntity mpEntity = new MultipartEntity();
    ContentBody cbFile = new FileBody(audioFile, "audio/AMR");
    mpEntity.addPart("audioFile", cbFile);

    httpPost.setEntity(mpEntity);

    HttpResponse response = null;
    try {
        response = httpClient.execute(httpPost);
        HttpEntity responseEntity = response.getEntity();
        System.out.println(response.getStatusLine());

        if(responseEntity != null) 
            System.out.println(EntityUtils.toString(responseEntity));

        if(responseEntity != null) {
            EntityUtils.consume(responseEntity);
        }

        httpClient.getConnectionManager().shutdown();

    } catch (ClientProtocolException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

It feels to me like the file is being attached and uploaded correctly.
I also tried doing it through HTML with a multipart/form-data post request, but the file still wasn’t found.

What am I doing wrong?

EDIT:
I removed the line at the beginning of the doPost() along with the if statement:

ServletFileUpload.isMultipartContent(request);

And then the upload worked correctly. Is it possible that this method consumes the request’s ‘input/output/whatever it is’ stream?

Thanks

Answer 1

EDIT: I removed the line at the beginning of the doPost() along with the if statement:

ServletFileUpload.isMultipartContent(request);

And then the upload worked correctly. Is it possible that this method consumes the request’s ‘input/output/whatever it is’ stream?

This is strange. All that method does is checking if the request method equals to POST and if the Content-Type header starts with multipart/. Here’s an extract of the source of the currently latest Commons FileUpload API version (which hasn’t changed much across years):

public static final boolean isMultipartContent(
        HttpServletRequest request) {
    if (!"post".equals(request.getMethod().toLowerCase())) {
        return false;
    }
    String contentType = request.getContentType();
    if (contentType == null) {
        return false;
    }
    if (contentType.toLowerCase().startsWith(MULTIPART)) {
        return true;
    }
    return false;
}

You see, nothing shocking.

Perhaps you’re using a very obscure/buggy servlet container which manifests a bug that the request body will implicitly be consumed when you call request.getMethod() or getContentType().