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/s         


        

Answer 1

From the HttpServletRequest#getQueryString() javadoc:

Returns: a String containing the query string or null if the URL contains no query string. The value is not decoded by the container.

Note the last statement. So you need to URL-decode it youself using java.net.URLDecoder.

String queryString = URLDecoder.decode(request.getQueryString(), "UTF-8");

However, the normal way to gather parameters is just using HttpServletRequest#getParameter().

String param = request.getParameter("param"); // così

The servletcontainer has already URL-decoded it for you then if you have configured it to use the correct encoding. The request.setCharacterEncoding() has only effect on the request body (POST) not on the request URI (GET). Also see Mirage's answer.