SpringMVC拦截器例子

1 界面登录验证

1.1 准备工作

1.1.1 导入servlet-api依赖

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>servlet-api</artifactId>
    <version>6.0.53</version>
</dependency>

1.1.2 创建员工控制类(EmpController类)

package com.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpSession;
@Controller
@RequestMapping("emps")
public class EmpController {
    @RequestMapping("find")
    public String find(){
        System.out.println("查询员工");
        return "index";
    }
    @RequestMapping("delete")
    public String delete(){
        System.out.println("删除员工");
        return "index";
    }
    @RequestMapping("add")
    public String add(){
        System.out.println("添加员工");
        return "index";
    }
}

1.2 在EmpController类里面创建登录和注销方法

//注意:登录后要把用户保存在session域中,注销后需要session域中的相关数据给清除掉
@RequestMapping("login")
    public String login(HttpSession session){
        session.setAttribute("users", "张三");
        return "index";
    }
@RequestMapping("logout")
    public String logout(HttpSession session){
        session.removeAttribute("users");
        return "index";
    }

1.3 创建登录拦截类(LoginInterceptor)

package com.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object users = request.getSession().getAttribute("users");
        if(users==null){
            System.out.println("被登录拦截器拦截了");
            request.setAttribute("msg", "请先登录");
            request.getRequestDispatcher("/index.jsp").forward(request, response);
            return false;
        }
        return true;
    }
}

1.4 在主配置文件SpringMvc2.xml里面进行拦截器的配置

<mvc:interceptor>
      <mvc:mapping path="/emps/**"/>
      <mvc:exclude-mapping path="/emps/find*"/>
      <mvc:exclude-mapping path="/emps/log*"/>
      <!--拦截器对象的地址-->
      <bean class="com.interceptor.LoginInterceptor"></bean>
</mvc:interceptor>

1.5 编写首页index.jsp页面

<%--
  Created by IntelliJ IDEA.
  User: SSS翱翔万里
  Date: 2022/11/13
  Time: 15:52
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
      <h1>进入了首页</h1>
      消息:${msg}<br>
      ${users==null ?'未登录':'已登录 用户:'}${users}
      <a href="/emps/login">登录</a>
      <a href="/emps/logout">注销</a><br>
      <a href="/emps/find">查询用户</a>
      <a href="/emps/delete">删除用户</a>
      <a href="/emps/add">添加用户</a>
</body>
</html>