SpringMVC拦截器

springmvc的拦截器

需求：进行用户的访问控制，判断用户是否登陆，如果登陆进行正常访问，如果没有登陆跳转到登陆页面。

1自定义拦截器类

 package org.guangsoft.utils;

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

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

 public class LoginInterceptor implements HandlerInterceptor
 {

     /***
      * afterCompletion:在整个handler中，处理请求的方法执行完毕，执行执行
      *  场景：统一的异常处理，日志记录，资源的释放
      * ****/
     @Override
     public void afterCompletion(HttpServletRequest request,
             HttpServletResponse response, Object obj, Exception exp)
             throws Exception
     {
     }

     /****
      * postHandle:进入handler中处理本次的请求的方法，在return ModelAndView之前执行
      * 场景：统一的model数据和view试图数据封装。
      *     日志记录
      * ***/
     @Override
     public void postHandle(HttpServletRequest request, HttpServletResponse response,
             Object obj, ModelAndView mv) throws Exception
     {
     }

     /***
      * preHandle:在handler（处理器的）处理请求的方法之前执行，只有该方法的返回值为true的情况下
      * 放行：才会执行handler中的方法：
      * 场景：权限控制，登陆的访问控制
      * ***/
     @Override
     public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
             Object obj) throws Exception
     {
         HttpSession session = request.getSession();
         //获得客户端发送请求的路径
         String url = request.getRequestURL().toString();
         //获得session中特定值
         Object user = session.getAttribute("user");
         if(user == null)
         {
             response.sendRedirect("login.jsp");//跳转到登陆页面
             return false;

         }
         return true;
     }

 } 

2进行拦截器配置

 <?xml version="1.0" encoding="UTF-8"?>
 <beans
     xmlns="http://www.springframework.org/schema/beans"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:p="http://www.springframework.org/schema/p"
     xsi:schemaLocation=
     "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
     http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">

     <!-- 开启扫描注解 -->
     <context:component-scan base-package="org.guangsoft.controller"></context:component-scan>
     <!-- 开启映射注解和适配注解 -->
     <mvc:annotation-driven></mvc:annotation-driven>
     <!--
     <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
         <property name="defaultEncoding" value="utf-8"></property>
         <property name="maxUploadSize" value="5000000"></property>
         <property name="uploadTempDir" value="/upload"></property>
     </bean>
     -->
     <mvc:interceptors>
         <mvc:interceptor>
             <mvc:mapping path="/**"/>
             <mvc:exclude-mapping path="/login.action"/>
             <bean class="org.guangsoft.utils.LoginInterceptor"></bean>
         </mvc:interceptor>
     </mvc:interceptors>
 </beans>