代码

package cn.itcast.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;import javax.servlet.annotation.WebFilter;public class DemoFilter implements Filter {    public DemoFilter() {    }    public void destroy() {    }    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {        // TODO Auto-generated method stub        // place your code here        request.setCharacterEncoding("UTF-8");        response.setCharacterEncoding("UTF-8");        System.out.println("这是自定义过滤器，设置字符编码集为UTF-8");        // pass the request along the filter chain        chain.doFilter(request, response);    }    /**     * @see Filter#init(FilterConfig)     */    public void init(FilterConfig fConfig) throws ServletException {        // TODO Auto-generated method stub        System.out.println("init: 初始化方法。。。");    }}

package com.demo.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 DemoServlet */@WebServlet("/DemoServlet")public class DemoServlet extends HttpServlet {    private static final long serialVersionUID = 1L;    /**     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)     */    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                        response.getWriter().append("这是经过过滤之后的输出");    }    /**     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)     */    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // TODO Auto-generated method stub        doGet(request, response);    }}

 

 将代码注释掉

 

 过滤之前的情况

 

 然后去掉注释

 

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