过滤器在Web开发应用------解决中文乱码

package com;

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 Encoding implements Filter{
protected String encoding=null;
protected FilterConfig config;
@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// TODO Auto-generated method stub
if(request.getCharacterEncoding()==null){
String encode=getEncoding();
if(encode!=null){
request.setCharacterEncoding(encode);
response.setCharacterEncoding(encode);
}
}
chain.doFilter(request, response);
}

@Override
public void init(FilterConfig config) throws ServletException {
// TODO Auto-generated method stub
this.config=config;
this.encoding=config.getInitParameter("Encode");
}

protected String getEncoding(){
return encoding;
}

}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>

<filter>
<filter-name>EncodeFilter</filter-name>
<filter-class>com.Encoding</filter-class>
<init-param>
<param-name>Encode</param-name>
<param-value>GB2312</param-value>
</init-param>
</filter>

<filter-mapping>
<filter-name>EncodeFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

</web-app>