登录拦截器

1、拦截器实现代码

package com.interceptor;

import java.util.List;

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

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

public class LoginInterceptor implements HandlerInterceptor{
    //允许那些url不被拦截，那些需要被拦截
    private List<String> allowedpass;
    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
        String urlString = request.getRequestURL().toString();
        //先判断session状态
        System.out.println("urlString="+urlString);
        System.out.println("allowedpass="+allowedpass);
        Object user = request.getSession().getAttribute("user");
        if(user!=null) {
            System.out.println("已登录，无需校验");
            return true;
        }
        for (String temp : allowedpass) {
            if(urlString.endsWith(temp)) {
                return true;
            }
        }
        response.sendRedirect(request.getContextPath()+"/login.jsp");
        return true;
    }
    @Override
    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
            throws Exception {
    }
    
    @Override
    public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
            throws Exception {
        
    }
    public List<String> getAllowedpass() {
        return allowedpass;
    }
    public void setAllowedpass(List<String> allowedpass) {
        this.allowedpass = allowedpass;
    }
    
    
    
}

2、Controller层代码

package com.controller;

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

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

@Controller
public class UserController {
    
    @RequestMapping("/login")
    public String login(User user,HttpSession session) {
        if("siggy".equals(user.getUsername())&&"1111".equals(user.getPwd())) {
            session.setAttribute("user", user);
            System.out.println(user.toString());
            return "redirect:/index.jsp";
        }
        return "redirect:/login.jsp";
    }
}

3、mvc.xml配置文件

<mvc:interceptor>
        <mvc:mapping path="/**"/>
        <bean class="com.interceptor.LoginInterceptor">
            <!-- 注入进来 -->
            <property name="allowedpass">
                <list>
                    <value>login.do</value>
                </list>
            </property>
        </bean>
    </mvc:interceptor>

4、login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>login</title>
</head>
<body>
<form action="login.do" method="post">
    username:<input type="text" name="username"><br>
    password:<input type="password" name="pwd"><br>
    <input type="submit" value="submit">

</form>
</body>
</html>

未登录时访问/admin/hello.do 被拦截，跳转到登陆页面

点击登陆

再次访问/admin/hello.do，访问成功。