04_过滤器Filter_05_Filter解决全站中文乱码问题（POST方式）

<?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" 
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" 
         id="WebApp_ID" version="3.0">
  <display-name>FilterDemo01</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>com.Higgin.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>charset</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern> <!-- 过滤所有 -->
    </filter-mapping> 
  
</web-app>

package com.Higgin.web.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ServletTest01
 */
@WebServlet("/ServletTest01")
public class ServletTest01 extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    public ServletTest01() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().write("中国 加油！China Come on!");
        System.out.println("执行ServletTest01---");
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }

}

package com.Higgin.web.filter;

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 CharacterEncodingFilter  implements Filter{

    private FilterConfig filterConfig=null;
    private String defaultCharset="UTF-8";  //自己先设计一个缺省的编码
    
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        this.filterConfig=filterConfig;
    }
    
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        
        System.out.println("进入doFilter()......");
        
        String charset=filterConfig.getInitParameter("charset"); //获取配置文件的charset的value
        if(charset==null){  //未成功获取charset,就将缺省的defaultCharset赋值给charset
            charset=defaultCharset;  
        }
        
        request.setCharacterEncoding(charset);
        response.setCharacterEncoding(charset);
        response.setContentType("text/html;character="+charset);
        
        chain.doFilter(request, response);//让目标资源执行，放行

    }
    
    @Override
    public void destroy() {
        
    }
    
}