Get form parameters from multipart request without getting the files

Question

I\'m looking for a way to get the form parameters of a HTTP multi-part request in a Servlet-filter without uploading files (yet).

request.getParameterMap() returns e

Answer 1

Just to add to the answers already provided - I had a very similar problem in that I was trying to add some CSRF validation to our existing web app. We decided to include a special token in each form using some JS and add a servlet filter to check that the token existed (therefore a generic, isolated solution).

The servlet would check if the token was present but broke for every form that provided a file upload option. Hence I landed at this page frequently while doing some googling.

The work around we used (while attempting to avoid any dealings with the uploaded files) was to get some JavaScript to add the token as a GET parameter, i.e. We modified the form's action URL to include the token and therefore could use the HttpServletRequest.getParameter() method for the token (and only the token).

I have tested this in IE, FF and Chrome and all seem to be happy.

Hope this helps anyone who also finds themselves in a similar situation.