Cookie完成十天免登录

短命女 2021-10-23 16:20 411阅读 0赞

Cookie也可以实现登录次数的限制，这里不做代码处理；

**Cookie最终保存在浏览器客户端上，Cookie可以将会话的状态保存在浏览器客户端上。**

登录时：

进入网站，网站首页是一个Servlet，获取浏览器发送的Cookie，

若是获取到用户名密码且验证成功则跳转成功页；

没有获取到约定好的用户名密码，则跳登录页，旅客输入登录用户名密码登录成功，服务器发送登录相关Cookie到浏览器；

**下面是具体的代码：**

**首先来画几个页面logn.html login-error.html login-success.html:**

<html>
    	<head>
    		<title>用户登录</title>
    		<meta charset="UTF-8">
    	</head>
    	<body>
    		<form action="/httpCookieDemo1/login" method="post">
    			用户名<input type="text" name="username"><br>
    			密码<input type="password" name="password"><br>
    			<input type="checkbox" name="tenDaysAutoLogin"  value="yes">十天内免登录<br>
    			<input type="submit" value="登录">
    		</form>
    	</body>
    </html>

**login-error.html:**

**login-success.html**

**web.xml配置：**

<?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">
    	
    	<welcome-file-list>
    		<welcome-file>system/checkLogin</welcome-file>
    	</welcome-file-list>
    	
    	<servlet>
    		<servlet-name>login</servlet-name>
    		<servlet-class>com.httpCookieDemo.LoginServlet</servlet-class>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>login</servlet-name>
    		<url-pattern>/login</url-pattern>
    	</servlet-mapping>
    	
    	<servlet>
    		<servlet-name>checkLogin</servlet-name>
    		<servlet-class>com.httpCookieDemo.CheckLoginServlet</servlet-class>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>checkLogin</servlet-name>
    		<url-pattern>/system/checkLogin</url-pattern>
    	</servlet-mapping>
    	
    </web-app>

**代码部分：**

package com.httpCookieDemo;
    
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import javax.servlet.ServletException;
    import javax.servlet.http.Cookie;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class LoginServlet extends HttpServlet {
    
    	@Override
    	protected void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		//解决POST请求乱码问题
    		request.setCharacterEncoding("UTF-8");
    		//获取用户名和密码
    		String username = request.getParameter("username");
    		String password = request.getParameter("password");
    		//连接数据库验证用户名和密码
    		Connection conn = null;
    		PreparedStatement ps = null;
    		ResultSet rs = null;
    		boolean loginSuccess = false;
    		try {
    			Class.forName("com.mysql.jdbc.Driver");
    			conn = DriverManager.getConnection("jdbc:mysql://localhost:3366/hr", "root", "112233");
    			String sql = "select * from t_user_info where username = ? and password = ?";
    			ps = conn.prepareStatement(sql);
    			ps.setString(1, username);
    			ps.setString(2, password);
    			rs = ps.executeQuery();
    			if(rs.next()){
    				loginSuccess = true;
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		} finally{
    			if(rs != null){
    				try {
    					rs.close();
    				} catch (SQLException e) {
    					e.printStackTrace();
    				}
    			}
    			if(ps != null){
    				try {
    					ps.close();
    				} catch (SQLException e) {
    					e.printStackTrace();
    				}
    			}
    			if(conn != null){
    				try {
    					conn.close();
    				} catch (SQLException e) {
    					e.printStackTrace();
    				}
    			}
    		}
    		
    		if(loginSuccess){
    			//登录成功
    			//查看用户是否选中了十天内免登录
    			if("yes".equals(request.getParameter("tenDaysAutoLogin"))){
    				//用户选择了十天内免登录功能
    				//创建Cookie对象
    				Cookie cookie = new Cookie("userInfo",username + "," + password); //userInfo="zhangsan,123"
    				//设置Cookie的有效期是10天
    				cookie.setMaxAge(60 * 60 * 24 * 10);
    				//设置Cookie关联路径
    				cookie.setPath(request.getContextPath());
    				//将Cookie发送给浏览器客户端
    				response.addCookie(cookie);
    			}
    			response.sendRedirect(request.getContextPath() + "/login-success.html");
    		}else{
    			//登录失败
    			response.sendRedirect(request.getContextPath() + "/login-error.html");
    		}
    	}
    }
    
    
    
    
    package com.httpCookieDemo;
    
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import javax.servlet.ServletException;
    import javax.servlet.http.Cookie;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class CheckLoginServlet extends HttpServlet {
    
    	@Override
    	protected void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		
    		String usernameAndPassword = null;
    		Cookie[] cookies = request.getCookies();
    		if(cookies != null){
    			for(Cookie cookie : cookies){
    				if("userInfo".equals(cookie.getName())){
    					usernameAndPassword = cookie.getValue();
    					break;
    				}
    			}
    		}
    		
    		if(usernameAndPassword != null){
    			String username = usernameAndPassword.split(",")[0];
    			String password = usernameAndPassword.split(",")[1];
    			//验证用户名和密码是否正确
    			Connection conn = null;
    			PreparedStatement ps = null;
    			ResultSet rs = null;
    			boolean loginSuccess = false;
    			try {
    				Class.forName("com.mysql.jdbc.Driver");
    				conn = DriverManager.getConnection("jdbc:mysql://localhost:3366/hr", "root", "112233");
    				String sql = "select * from t_user where username = ? and password = ?";
    				ps = conn.prepareStatement(sql);
    				ps.setString(1, username);
    				ps.setString(2, password);
    				rs = ps.executeQuery();
    				if(rs.next()){
    					loginSuccess = true;
    				}
    			} catch (Exception e) {
    				e.printStackTrace();
    			} finally{
    				if(rs != null){
    					try {
    						rs.close();
    					} catch (SQLException e) {
    						e.printStackTrace();
    					}
    				}
    				if(ps != null){
    					try {
    						ps.close();
    					} catch (SQLException e) {
    						e.printStackTrace();
    					}
    				}
    				if(conn != null){
    					try {
    						conn.close();
    					} catch (SQLException e) {
    						e.printStackTrace();
    					}
    				}
    			}
    			
    			if(loginSuccess){
    				//登录成功
    				response.sendRedirect(request.getContextPath() + "/login-success.html");
    			}else{
    				//登录失败
    				response.sendRedirect(request.getContextPath() + "/login.html");
    			}
    		}else{
    			response.sendRedirect(request.getContextPath() + "/login.html");
    		}
    	}
    }

**希望对你有帮助，祝你有一个好心情，加油！**

**若有错误、不全、可优化的点，欢迎纠正与补充！**