练习Servlet过滤器代码-原创手记-慕课网

登录成功界面和失败界面就不发了，很简单

登录界面login.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'login.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>

  <body>
    <center>
    <h1>登录界面</h1>
    <hr>
    <form action="<%=request.getContextPath()%>/servlet/LoginServlet" method="post">
        账号:<input type="text" name="username"><br>
        密码:<input type="password" name="password"><br>
        <input type="submit" value="提交" name="submit">
        &nbsp;&nbsp;&nbsp;&nbsp;
        <input type="reset" value="重置" name="reset">
    </form>
    </center>
  </body>
</html>

Web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 <filter>
  <filter-name>LoginFilter</filter-name>
  <filter-class>com.imooc.filter.LoginFilter</filter-class>
  <init-param>
   <param-name>keywords</param-name>
   <param-value>login.jsp;failure.jsp;LoginServlet;</param-value>
  </init-param>
 </filter>
 <filter-mapping>
  <filter-name>LoginFilter</filter-name>
  <url-pattern>/*</url-pattern>
  <dispatcher>REQUEST</dispatcher>
 </filter-mapping>
 <servlet>
  <description>This is the description of my J2EE component</description>
  <display-name>This is the display name of my J2EE component</display-name>
  <servlet-name>LoginServlet</servlet-name>
  <servlet-class>com.imooc.servlet.LoginServlet</servlet-class>
 </servlet>
 <servlet-mapping>
  <servlet-name>LoginServlet</servlet-name>
  <url-pattern>/servlet/LoginServlet</url-pattern>
 </servlet-mapping>
 <welcome-file-list>
  <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>
 <login-config>
  <auth-method>BASIC</auth-method>
 </login-config>
</web-app>

LoginServlet
(简单处理)

package com.imooc.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {
    public LoginServlet() {
        super();
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();

        out.close();
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();

        String username = request.getParameter("username");
        String password = request.getParameter("password");
        request.getSession().setAttribute("username", username);
        if ("admit".equals(username) && "admit".equals(password)) {
            response.sendRedirect("../success.jsp");
        } else {
            response.sendRedirect("../failure.jsp");
        }
        out.close();
    }
}

过滤器LoginFilter

package com.imooc.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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginFilter implements Filter {

    private FilterConfig config;

    public void destroy() {
        // TODO Auto-generated method stub

    }

    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain arg2) throws IOException, ServletException {
        HttpServletRequest request=(HttpServletRequest) arg0;
        HttpServletResponse response= (HttpServletResponse) arg1;

        String init=config.getInitParameter("keywords");
        String[] words=init.split(";");
        for (String str : words) {
            if(request.getRequestURI().indexOf(str)!=-1){
                arg2.doFilter(arg0, arg1);
                return;
            }
        }

        String username=(String) request.getSession().getAttribute("username");
        if(username!=null&&!(username.equals(""))){
            arg2.doFilter(arg0, arg1);
        }
        else{
            response.sendRedirect("login.jsp");
        }

    }

    public void init(FilterConfig arg0) throws ServletException {
        config=arg0;

    }
}