SpringMVC自定义拦截器登录检测功能的实现代码

一、定义登录控制器

目录结构

代码：

1、创建TUser类

2、创建LoginController类

页面代码:

1、login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>login</title>
</head>
<body>
<h1>${msg}</h1>
<form id="login" action="${pageContext.request.contextPath}/user/doLogin" method="post">
用户名：<input type="text" name="name"/><br/>
密码：<input type="password" name="password"><br/>
<input type="submit">
</form>
</body>
</html>

2、loginFail.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>loginFail</title>
</head>
<body>
<h1>${msg}</h1>
<h2><a href="${pageContext.request.contextPath}/user/loginOut" rel="external nofollow" rel="external nofollow" >返回登录界面</a></h2>
</body>
</html>

3、success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>success</title>
</head>
<body>
${msg}
<h2><a href="${pageContext.request.contextPath}/user/loginOut" rel="external nofollow" rel="external nofollow" >退出登录</a></h2>
</body>
</html>

代码：

1、创建LoginInterceptor类，作为拦截器类需实现HandlerInterceptor，并重写里面的三个方法preHandle、postHandle、afterCompletion：

package com.demo.interceptor;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
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 {
System.out.println("LoginInterceptor preHandle");
//放行：判断什么情况下
//1、请求到登陆界面放行,首次登陆
if(request.getRequestURI().contains("login")||request.getRequestURI().contains("doLogin")){
return true;
}
//2、退出登录可直接放行
if(request.getRequestURI().contains("loginOut")){
return true;
}
//3、通过登录进入放行
if(request.getSession().getAttribute("user")!=null){
return true;
}
//非法请求进行拦截
//重定向到登录页面
response.sendRedirect(request.getContextPath()+"login");
//拦截
return false;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response,
Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("LoginInterceptor "+"postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
Object handler, Exception ex) throws Exception {
System.out.println("LoginInterceptor "+"afterCompletion");
}
}