Using Spring 3 @ExceptionHandler with commons FileUpload and SizeLimitExceededException/MaxUploadSizeExceededException

Question

I am having trouble with catching and gracefully handling commons fileupload's FileUploadBase.SizeLimitExceededException or spring's MaxUploadSizeExceededException when uploading large files.

From what I can tell these exceptions are thrown during data binding, before the controller is actually reached, therefore resulting in a 500 and no calling of the exception handler method. Has anyone come across this before, and what is the best way for handling these exceptions properly?

Answer 1

thanks to thetoolman for this simple solution. I extended it a bit. I wanted to leave the file handling untouched and transport the Exception to the Controller.

package myCompany; 

public class DropOversizeFilesMultipartResolver extends CommonsMultipartResolver {

    /**
     * Parse the given servlet request, resolving its multipart elements.
     * 
     * Thanks Alexander Semenov @ http://forum.springsource.org/showthread.php?62586
     * 
     * @param request
     *            the request to parse
     * @return the parsing result
     */
    @Override
    protected MultipartParsingResult parseRequest(final HttpServletRequest request) {

        String encoding = determineEncoding(request);
        FileUpload fileUpload = prepareFileUpload(encoding);

        List fileItems;

        try {
            fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
        } catch (FileUploadBase.SizeLimitExceededException ex) {
            request.setAttribute(EXCEPTION_KEY, ex);
            fileItems = Collections.EMPTY_LIST;
        } catch (FileUploadException ex) {
            throw new MultipartException("Could not parse multipart servlet request", ex);
        }

        return parseFileItems(fileItems, encoding);
    }
}

and in the controller

  @InitBinder("fileForm")
  protected void initBinderDesignForm(WebDataBinder binder) {
    binder.setValidator(new FileFormValidator());
  }

    @RequestMapping(value = "/my/mapping", method = RequestMethod.POST)
  public ModelAndView acceptFile(HttpServletRequest request, Model model, FormData formData,
      BindingResult result) {

    Object exception = request.getAttribute(DropOversizeFilesMultipartResolver.EXCEPTION_KEY);
    if (exception != null && FileUploadBase.SizeLimitExceededException.class.equals(exception.getClass())) {
      result.rejectValue("file", "<your.message.key>");
      LOGGER.error(exception);
    }

the spring config remains the same. It would be really nice to have the exception transported to the validator, but I haven't figured out how to do this yet.