Jsp与Servlet之使用安全 jsp 开发用户登录、退出、显示当前登录界面

使用安全 jsp 开发用户登录、退出、显示当前登录界面

一、创建项目相关步骤截图

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注意：记得点击确认

创建jsp文件夹
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二、相关代码展示

①index.jsp

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
    <title>首页</title>
</head>
<body>
<h1>欢迎${UserInfo}登录</h1>
<a href="logout">退出登录</a>
</body>
</html>

②login.jsp代码

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录页</title>
</head>
<body>
<form action="login" method="post">
    <input name="username" value="${username}">
    <input name="password" value="${password}">
    <input type="submit" value="登录">
    <p style="color: red">${msg}</p>
</form>
</body>
</html>

③filter下面的MyFilter代码

package com.example.demo.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebFilter("/*")
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request= (HttpServletRequest) servletRequest;
        HttpServletResponse response= (HttpServletResponse) servletResponse;
        if (request.getRequestURI().endsWith("login")) {
            filterChain.doFilter(request,response);
            return;
        }
        if (request.getSession().getAttribute("UserInfo")!=null) {
            filterChain.doFilter(request,response);
            return;
        }
        response.sendRedirect("login");
    }

    @Override
    public void destroy() {
    }
}

④listener下面的MyServletContextListener代码

package com.example.demo.listener;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class MyServletContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("项目启动了");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("项目停止了");
    }
}

⑤servlet下面的IndexServlet代码

package com.example.demo.servlet;

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 java.io.IOException;
@WebServlet("/index")
public class IndexServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.getRequestDispatcher("/WEB-INF/jsp/index.jsp").forward(request,response);
    }
}

⑥servlet下面的LoginServlet代码

package com.example.demo.servlet;

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 java.io.IOException;
@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        if ("admin".equals(username)&&"123456".equals(password)) {
            request.getSession().setAttribute("UserInfo",username);
            response.sendRedirect("index");
        }else {
            request.setAttribute("username",username);
            request.setAttribute("password",password);
            request.setAttribute("msg","账号或密码错误！！！");
            request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        }
    }
}

⑦servlet下面的LogoutServlet代码

package com.example.demo.servlet;

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 java.io.IOException;
@WebServlet("/logout")
public class LogoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.getSession().invalidate();
        //response.sendRedirect("index");
    }
}

三、测试结果

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