LoginInterceptor

package com.lan.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("user")
public class LoginController {
    @RequestMapping("/main")
    public String main(){
        return "main";
    }
    @RequestMapping("/goLogin")
    public String login(){

        return "login";
    }
    @RequestMapping("/login")
    public String login(HttpSession session, String username, Model model){
        //把用户信息存到Session中
        session.setAttribute("userLoginInfo",username);
        model.addAttribute("username",username);

        return "main";
    }
    @RequestMapping("/goOut")
    public String goOut(HttpSession session){
        //把用户信息存到Session中
        //session.invalidate();//销毁
        session.removeAttribute("userLoginInfo");//移出session
        return "login";
    }
}

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

  
    
  
  

    
登陆页面
    
首页

  

拦截器：LoginInterceptor

package com.lan.config;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //登陆页面也会放行:http://localhost:8080/goLogin
        //contains("goLogin"):URL包含login就放行
        if (request.getRequestURI().contains("login")){
            return true;
        }

        //放行的判断
        HttpSession session = request.getSession();
        if (session.getAttribute("userLoginInfo") != null){
            return true;
        }
        //判断什么情况下没有登陆
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        return false;

    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


    
登陆页面
    

        用户名:
        密  码:
        
    

main.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


    
首页
    ${username}
    

        注销