springMVC 配置CharacterEncodingFilter之后不起效果

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最近开始自学springMVC框架，遇到中文乱码这一经典问题，记录下解决过程，以便后续忘记

web.xml 里过滤器配置如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
    <display-name>springmvc</display-name>
    
    <!-- 解决中文编码问题 -->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    
    <!-- <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping> -->
    
    <servlet>
        <servlet-name>example</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        
        <!-- init-param 节点必须在 load-on-startup 节点以上 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-servlet.xml</param-value>
        </init-param>
        
        <load-on-startup>1</load-on-startup>
        
    </servlet>
    
    <servlet-mapping>
         <servlet-name>example</servlet-name>
         <url-pattern>*.do</url-pattern>
    </servlet-mapping>
    
    <welcome-file-list>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>

spring配置文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.guo.controller"></context:component-scan>
    
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
        p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" >
        
        <!-- 如果使用 jstl 的话，配置下面的属性 
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property>
        -->
    </bean>
    
</beans>

jsp代码如下：

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
</head>
<body>

    欢迎您，${requestScope.username }

</body>
</html>

java的controller代码如下：

/*
 * 文 件 名:  UserController.java
 * 版    权:   Ltd. Copyright YYYY-YYYY,  All rights reserved
 * 描    述:  <描述>
 * 修 改 人:  Administrator
 * 修改时间:  2016年3月17日
 */
package com.guo.controller;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.guo.po.User;

/**
 * <一句话功能简述>
 * <功能详细描述>
 * 
 * @author  Administrator 2016年3月17日
 */
@Controller
@RequestMapping("/user")
public class UserController
{
    // Controller 单例
    // http://localhost:8080/springmvc/user/add.do
    @RequestMapping("/add")
    public void add(User user)
    {
        System.out.println(user);
    }
    
    @RequestMapping("/login")
    public String login(@RequestParam("n")String userName, @RequestParam("p")String password, ModelMap map)
    {
        //userName = new String(userName.getBytes("ISO-8859-1"), "UTF-8");
        
        System.out.println("userName is " + userName
                + " and password is " + password);
        
        // session.setAttribute
        // request.setAttribute
        
         map.put("username", userName);
         
//        return "forward:/welcome.jsp";
         
        return "admin/adminwelcome";
    }
    
    @RequestMapping("/login2")
    public ModelAndView login2(@RequestParam("n")String userName, @RequestParam("p")String password)
    {
        System.out.println("userName is " + userName
                + " and password is " + password);
        
         ModelAndView mv = new ModelAndView();
         mv.setViewName("admin/adminwelcome");
         
         mv.getModelMap().put("username", userName);
         
         
        return mv;
    }
    
    @RequestMapping("/baidu")
    public String baidu()
    {
      return "redirect:http://www.baidu.com";
    }
    
    @RequestMapping("{id}/delete")
    public void delete(@PathVariable("id")Integer id)
    {
        System.out.println("delete id is " + id);
    }
}