使用Java servlet实现自动登录退出功能

时间：2021-05-19

UserDao.java从数据库中查询用户名与密码

//登录public User login(User user) throws SQLException {QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());String sql = "select from user where username = ? and password = ?";return qr.query(sql, new BeanHandler<User>(User.class),user.getUsername(),user.getPassword());}UserService.javapublic User login(User user){try {return ud.login(user);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}

UserServlet.java实现登录功能

//登录public void login(HttpServletRequest request,HttpServletResponse response) throws IOException, IllegalAccessException, InvocationTargetException, ServletException{Map<String,String[]> map = request.getParameterMap();User user = new User();BeanUtils.populate(user,map);if (map.get("autoLogin")!=null){Cookie username = new Cookie("username", map.get("username")[0]);username.setMaxAge(6060);Cookie password = new Cookie("password", map.get("password")[0]);password.setMaxAge(60*60);response.addCookie(username);response.addCookie(password);}user = us.login(user);if (user != null){request.getSession().setAttribute("user", user);response.sendRedirect("/ShopStore/default.jsp");}else{request.setAttribute("message", "用户或密码错误！");request.getRequestDispatcher("/login.jsp").forward(request, response);}}

工具类:AutoLoginFilter.java用来实现自动登录

package com.yinhe.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;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.yinhe.bean.User;import com.yinhe.service.UserService;public class AutoLoginFilter implements Filter{br/>@Overridepublic void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {HttpServletRequest req = (HttpServletRequest)request;HttpServletResponse resp = (HttpServletResponse)response;//是否已登录if (req.getSession().getAttribute("user") == null){//如果已登录，则啥都不干//判断cookie中有没有账户密码Cookie[] cookies = req.getCookies();if (cookies != null){String username = "";String userpass = "";for (Cookie cookie : cookies) {if (cookie.getName().equals("username")){//找到感兴趣的cookieusername = cookie.getValue();}if (cookie.getName().equals("password")){//找到感兴趣的cookieuserpass = cookie.getValue();}}UserService us = new UserService();User user = new User();user.setUsername(username);user.setPassword(userpass);if (us.login(user) != null){req.getSession().setAttribute("user", user);}}}chain.doFilter(request, response);br/>}@Overridepublic void init(FilterConfig filterConfig) throws ServletException {// TODO Auto-generated method stubbr/>}@Overridepublic void destroy() {// TODO Auto-generated method stub}}

前台:login.jsp此单选框被选中下次访问即为自动登录

<div class="checkbox"><label> <input type="checkbox" name="autoLogin" > 自动登录</label> <label> <inputtype="checkbox" > 记住用户名</label></div><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head><title>系统首页</title><style>#nav{height: 88px;padding: 5px 200px;background-color: aquamarine;}#logo{float: left;}#userinfo{float: right;height: 50px;line-height: 80px;}#container{background-color: aqua;height: 800px;margin: 2px 200px;font-size: xx-large;text-align: center;}</style></head><body><div id="nav"><div id="logo"><img src="csdn-logo.png" width="180" height="88"></div><div id="userinfo"><%-- 不推荐使用<%String loginUser = (String) request.getAttribute("loginUser");if (loginUser != null){out.println(loginUser);}else {%><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a><a>/注册</a><%}%>--%><%String loginUser = (String) session.getAttribute("loginUser");if (loginUser != null){out.println(loginUser);out.println("<a href='logoutServlet'>退出</a>");}else {%><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a><a>/注册</a><%}%></div></div><div id="container">

主页内容

<a href="info.jsp" rel="external nofollow" >Python——画一棵漂亮的樱花树（不同种樱花+玫瑰+圣诞树喔）</a></div></body></html>login.jsp<%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head><title>登录</title><style>tr{height:50px;}td{text-align: center;}</style></head><body><%String msg = (String)request.getAttribute("msg");%><%if(msg != null){out.print(msg);}%><form action="myServlet02" method="get"><h1 align="center">登录</h1><table width="500" border="1" cellspacing="0" cellpadding="0" align="center"><tr><td>账号：</td><td><input type="text" name="username" /></td></tr><tr><td>密码：</td><td><input type="password" name="password" /></td></tr><tr><td colspan="2"><input type="submit" value="登录" /></td></tr></table></form></body></html>

info.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head><title>Title</title><style>#nav{height: 88px;padding: 5px 200px;background-color: aquamarine;}#logo{float: left;}#userinfo{float: right;height: 50px;line-height: 80px;}#container{background-color: aqua;height: 800px;margin: 2px 200px;font-size: xx-large;text-align: center;}</style></head><body><div id="nav"><div id="logo"><img src="csdn-logo.png" width="180" height="88"></div><div id="userinfo"><%String loginUser = (String) session.getAttribute("loginUser");if (loginUser != null){out.println(loginUser);out.println("<a href='logoutServlet'>退出</a>");}else {%><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a><a>/注册</a><%}%></div></div><div id="container">主页内容</div></body></html>

Servlet02.java

import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;br/>@WebServlet("/myServlet02")public class Servlet02 extends HttpServlet {protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//修改编码request.setCharacterEncoding("utf-8");//请求过来的编码是亨达返佣e-file-list></web-app>

总结

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