I think in your web-app you should use Filter, which will calls
request.setCharacterEncoding("WhatDoYouWant") because overwise,
according to spec, server should set request encoding to iso-8859-1.

There is an example:

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class CharsetFilter implements Filter
{
 // charset
 private String encoding;

 public void init(FilterConfig config) throws ServletException
 {
  // read from config
  encoding = config.getInitParameter("requestEncoding");

  // default
  if( encoding==null ) encoding="UTF8";
 }

 public void doFilter(ServletRequest request, ServletResponse response,
FilterChain next)
 throws IOException, ServletException
 {
  request.setCharacterEncoding(encoding);
  next.doFilter(request, response);
 }

 public void destroy(){}
}

And configuration:

<!-- CharsetFilter -->
  <filter>
    <filter-name>Charset Filter</filter-name>
    <filter-class>CharsetFilter</filter-class>
      <init-param>
        <param-name>requestEncoding</param-name>
        <param-value>UTF8</param-value>
      </init-param>
  </filter>

 <!-- CharsetFilter mapping -->
  <filter-mapping>
    <filter-name>Charset Filter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

Hope this helps.

--
WBR,
Serge.