5 Cookie和Session案例开发

绝地灬酷狼 2023-09-30 20:23 3阅读 0赞

案例:通过HttpSession判断用户是否登录

需求:实现登录一次即可,在一次会话内,可以反复多次访问WEB-INF/ welcome.html,如果没有登录过,跳转到登录页,登录成功后,可以访问

项目结构:

![f20be4adfd0daeabfca5e7e0e0841e52.png][]

组件介绍:

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <form method="get" action="loginServlet.do">
        用户名:<input type="text" name="username" ><br/>
        密码:<input type="password" name="password" ><br/>
        <input type="submit" >
    </form>
    </body>
    </html>

![0103055f50e3bde44fcfdb83a2464629.gif][]

![8cfb93a7365dd772d21cda5aebf8a85a.gif][]

登录成功之后可以访问的资源

main.html

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
       this is main page
    </body>
    </html>

![0fe94366198a0fd1fdc91ce218a30c54.gif][]

![7a750ee50b89a9029486c73708c31b88.gif][]

LoginServlet

用来校验登录的,登录成功将用户信息存户HttpSession,否则回到登录页

package com.msb.servlet;
    import com.msb.pojo.User;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    @WebServlet(urlPatterns = "/loginServlet.do")
    public class LoginServlet extends HttpServlet {
        @Override
        protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            // 获取用户名和密码
            String username = req.getParameter("username");
            String password = req.getParameter("password");
            // 如果用户名和密码为 msb 1234
            if("msb".equals(username)  && "1234".equals(password)){
                // 将用户信息放在HTTPSession中
                User user =new User(null, null, "msb", "1234");
                HttpSession session = req.getSession();
                session.setAttribute("user", user);
                // 登录成功 跳转至 main.html
                resp.sendRedirect(req.getContextPath()+"/mainServlet.do");
            }else{
                // 登录失败 回到login.html
                resp.sendRedirect(req.getContextPath()+"/login.html");
            }
        }
    }

![a494cefeac946641587cbfde1d73d7ad.gif][]

![f6e0151ef0b123cfbfc12236a0d8e9df.gif][]

MainServlet

用来向main.html中跳转的,同时验证登录,登录过,可以直接跳转,否则回到登录页

package com.msb.servlet;
    import com.msb.pojo.User;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    import java.util.logging.Handler;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    @WebServlet(urlPatterns = "/mainServlet.do")
    public class MainServlet extends HttpServlet {
        @Override
        protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            //跳转至main.html
            HttpSession session = req.getSession();
            User user = (User)session.getAttribute("user");
            if(null != user){
                // 判断如果登录过 允许跳转  HTTPSession中如果有登陆过的信息
                req.getRequestDispatcher("/WEB-INF/main.html").forward(req,resp);
            }else{
                // 如果没有登录过 回到登录去登录  HTTPSession中如果有登陆过的信息
                resp.sendRedirect("login.html");
            }
        }
    }

![821ee2b943639cd6ffe665cb78f6bb1f.gif][]

![57e8972697b48b7fbe0085f9763bb80b.gif][]

User

用来存储一个用户的信息的实体类对象

public class User implements Serializable {
        private Integer uid;
        private String realname;
        private String username;
        private String pasword;

![2068fcc327742de62d3b3e2d1c22c46c.gif][]

![ee8159c5aa72c80414a834e6f9a9cc0b.gif][]

[f20be4adfd0daeabfca5e7e0e0841e52.png]: https://img-blog.csdnimg.cn/img_convert/f20be4adfd0daeabfca5e7e0e0841e52.png
[0103055f50e3bde44fcfdb83a2464629.gif]: https://img-blog.csdnimg.cn/img_convert/0103055f50e3bde44fcfdb83a2464629.gif
[8cfb93a7365dd772d21cda5aebf8a85a.gif]: https://img-blog.csdnimg.cn/img_convert/8cfb93a7365dd772d21cda5aebf8a85a.gif
[0fe94366198a0fd1fdc91ce218a30c54.gif]: https://img-blog.csdnimg.cn/img_convert/0fe94366198a0fd1fdc91ce218a30c54.gif
[7a750ee50b89a9029486c73708c31b88.gif]: https://img-blog.csdnimg.cn/img_convert/7a750ee50b89a9029486c73708c31b88.gif
[a494cefeac946641587cbfde1d73d7ad.gif]: https://img-blog.csdnimg.cn/img_convert/a494cefeac946641587cbfde1d73d7ad.gif
[f6e0151ef0b123cfbfc12236a0d8e9df.gif]: https://img-blog.csdnimg.cn/img_convert/f6e0151ef0b123cfbfc12236a0d8e9df.gif
[821ee2b943639cd6ffe665cb78f6bb1f.gif]: https://img-blog.csdnimg.cn/img_convert/821ee2b943639cd6ffe665cb78f6bb1f.gif
[57e8972697b48b7fbe0085f9763bb80b.gif]: https://img-blog.csdnimg.cn/img_convert/57e8972697b48b7fbe0085f9763bb80b.gif
[2068fcc327742de62d3b3e2d1c22c46c.gif]: https://img-blog.csdnimg.cn/img_convert/2068fcc327742de62d3b3e2d1c22c46c.gif
[ee8159c5aa72c80414a834e6f9a9cc0b.gif]: https://img-blog.csdnimg.cn/img_convert/ee8159c5aa72c80414a834e6f9a9cc0b.gif