1.创建动态web项目
2.创建filters的文件
3.创建主页面
4.配置xml项目
总结构
主页面代码
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html><html><head><meta charset="UTF-8"><title>过滤器</title></head><body><form action="result.jsp">用户名：<input type="text" name="user">密码：<input type="text" name="pw"><input type="submit" value="提交"></form></body></html> <%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title></head><body><!-- 过滤器要加在接受请求页面的或服务器上 --><%String s=request.getParameter("user");out.print(s);%></body></html>package filter_test;
//filter是一个特殊的servlet类，有自己的生命周期，包括初始化，处理请求和相应，销毁等阶段
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;
import javax.servlet.http.HttpFilter;/*** Servlet Filter implementation class Filter01*/
@WebFilter("/Filter01")
public class Filter01 extends HttpFilter implements Filter {/*** @see HttpFilter#HttpFilter()*/public Filter01() {super();// TODO Auto-generated constructor stub}/*** @see Filter#destroy()*/public void destroy() {System.out.println("销毁...");// TODO Auto-generated method stub}/*** @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)*/public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {// TODO Auto-generated method stub// place your code hereSystem.out.println("过滤...");// pass the request along the filter chainchain.doFilter(request, response);}/*** @see Filter#init(FilterConfig)*/public void init(FilterConfig fConfig) throws ServletException {System.out.println("初始化...");// TODO Auto-generated method stub}}
