request.getQueryString() seems to need some encoding

Question

I have some problem with UTF-8. My client (realized in GWT) make a request to my servlet, with some parametres in the URL, as follow:

http://localhost:8080/servlet?param=value

When in the servlet I retrieve the URL, I have some problem with UTF-8 characters. I use this code:

protected void service(HttpServletRequest request, HttpServletResponse response) 
                    throws ServletException, IOException {

        request.setCharacterEncoding("UTF-8");

        String reqUrl = request.getRequestURL().toString(); 
        String queryString = request.getQueryString();
        System.out.println("Request: "+reqUrl + "?" + queryString);
        ...

So, if I call this url:

http://localhost:8080/servlet?param=così

the result is like this:

Request: http://localhost:8080/servlet?param=cos%C3%AC

What can I do to set up properly the character encoding?

Answer 1

I've run into this same problem before. Not sure what Java servlet container you're using, but at least in Tomcat 5.x (not sure about 6.x) the request.setCharacterEncoding() method doesn't really have an effect on GET parameters. By the time your servlet runs, GET parameters have already been decoded by Tomcat, so setCharacterEncoding won't do anything.

Two ways to get around this:

1. Change the URIEncoding setting for your connector to UTF-8. See http://tomcat.apache.org/tomcat-5.5-doc/config/http.html.

2. As BalusC suggests, decode the query string yourself, and manually parse it (as opposed to using the ServletRequest APIs) into a parameter map yourself.

Hope this helps!