急！字符编码过滤器问题！！！
加个过滤器，但是没效果，发现doFilter()方法根本没执行！init()方法执行了！web.xml没配置错！这是为什么？
[code=Java][/code]
MyFilter.java

package com.duyuan;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyFilter implements Filter {
private String encoding=null;
public void destroy() {
// TODO Auto-generated method stub
}
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
System.out.println("Filter執行！！！");
HttpServletRequest req=(HttpServletRequest)arg0;
HttpServletResponse res=(HttpServletResponse)arg1;
if(encoding!=null){
req.setCharacterEncoding(encoding);
res.setCharacterEncoding(encoding);
res.setContentType("text/html;charset="+encoding);
}
arg2.doFilter(req, res);
}
public void init(FilterConfig arg0) throws ServletException {
encoding=arg0.getInitParameter(encoding);
  System.out.println("Filter初始化！！！");
}
}




------解决方案--------------------
你确定你的配置没错么？？我之前写的一段代码，可以用，你试试！
package com.jy.util;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class CharacterFilter implements Filter {

@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {

arg0.setCharacterEncoding("gbk");
arg1.setCharacterEncoding("gbk");

arg2.doFilter(arg0, arg1);
}

@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub

}

}