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>