SpringMVC拦截器――实现登录验证拦截器的示例代码

本篇文章主要介绍了SpringMVC拦截器――实现登录验证拦截器的示例代码，具有一定的参考价值，感兴趣的小伙伴们可以参考一下。

本例实现登陆时的验证拦截，采用SpringMVC拦截器来实现

当用户点击到网站主页时要进行拦截，用户登录了才能进入网站主页，否则进入登陆页面

核心代码

首先是index.jsp,显示链接

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>  首页  登陆
用户中心
触发异常

controller类

 package com.jikexueyuan.demo.springmvc.lesson4.controller; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RequestParam; import com.jikexueyuan.demo.springmvc.lesson4.constant.Global; import com.jikexueyuan.demo.springmvc.lesson4.exception.MyException; import com.jikexueyuan.demo.springmvc.lesson4.model.User; import com.jikexueyuan.demo.springmvc.lesson4.service.LoginService; /** * 这个例子讲解了如何定义MVC三层注解，使用@Resource进行注入，以及使用@RequestMapping、@RequestParam 、@SessionAttributes */ @Controller public class LoginController extends BaseController { @Resource LoginService service; @Resource HttpServletRequest request; @RequestMapping("/exception") public void exception() throws MyException{ throw new MyException("测试springmvc中的异常捕获"); } @RequestMapping("/loginpage") public String toLoginPage(){ return "/WEB-INF/jsp/login.jsp"; } @RequestMapping("/user/home") public String toUserHome(){ return "/WEB-INF/jsp/userhome.jsp"; } @RequestMapping("/logout") public String logout(){ request.getSession().removeAttribute(Global.USER_SESSION_KEY); return "redirect:/"; } @RequestMapping(value = "/doLogin", method = RequestMethod.POST) public String doLogin(@RequestParam String userName, @RequestParam String password){ try { User user = service.doLogin(userName, password); request.getSession().setAttribute(Global.USER_SESSION_KEY, user); return "redirect:/user/home.html"; } catch (Exception e) { return "/WEB-INF/jsp/login.jsp"; } } }

当点击用户中心时，触发拦截，相关配置如下

在spring-mvc.xml中加上拦截配置，拦截所有URL中包含/user/的请求，当然请求用户中心时就会触发这个拦截器了

然后是bean指向的具体的interceptor类，如果session保存的用户信息为null，则跳到login页面，postHandle和afterCompletion方法都不执行，反之都执行。

 package com.jikexueyuan.demo.springmvc.lesson4.interceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; import com.jikexueyuan.demo.springmvc.lesson4.constant.Global; public class LoginInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { Object user = request.getSession().getAttribute(Global.USER_SESSION_KEY); if (user == null) { System.out.println("尚未登录，调到登录页面"); response.sendRedirect("/loginpage.html"); return false; } return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("postHandle"); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("afterCompletion"); } }

至此，简单的springmvc拦截器就完成了。

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