Encoding problem

[Sam Wang]

I have a Encodefilter which runs well on struts + tomcat4.
[Encodefilter]
...
request.setCharacterEncoding(encoding);
response.setContentType(contentType);
...
Now I start a new projection bases on webwork + hibernate + tomcat5.
I use the Encodefilter as a filter to url /*,and write a jsp like this:
[JSP]
<%@page contentType="text/html" %>
<%@page pageEncoding="GBK"%>
...
<META HTTP-EQUIV="content-type" CONTENT="text/html; charset=GBK">
...
The page can show chinese and english,but can't pass the chinese request parameter(it show the chinese with "???").
I watch my console,I find before the Encodefilter's doFilter(),the param is
already "???".
I don't know what's wrong.Is webwork or something else?