How to change the character encoding for Servlet 3.0 Spring MVC multipart upload forms?

Question

I have a pretty simple JSP/Servlet 3.0/Spring MVC 3.1 application.

On one of my pages, I have multiple forms. One of these forms allows the user to upload a file and

Answer 1

I also had the problem with encoding when using the Servlet 3 API. After some research, I have found that there is a bug in Tomcat 7 which makes the parameters not to be read with the correct encoding under certain conditions. There is a work-around. First, you need to tell which encoding it actually is (if it is not default iso-8859-1):

request.setCharacterEncoding("UTF-8");

This is basically what the CharacterEncodingFilter in Spring does. Nothing strange so far. Now the trick. Call this:

request.getParameterNames()

Make sure this method is invoked before getParts(). If you are using Spring I guess you need to do this in a filter before the request ends up in Spring. The order which the methods are invoked are crucial.

Update: The Tomcat bug has been fixed in 7.0.41 onwards, so if you use a recent version of Tomcat you only need to set the character encoding to get correct result.