拦截器

一、首先写一个类实现HandlerInterceptor，

　　实现HandlerInterceptor中的方法。

　　将preHandler 的返回值写成true，若不该就不会执行后面请求的方法了。

package com.neuedu.interceptor;

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

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

public class Inteceptor1 implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        // TODO Auto-generated method stub
        System.out.println("preHandle");
        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");

    }

}

二、在SpringMVC的配置文件中，我的是SpringMVC.xml配置interceptor

　　使用<mvc>的标签

<mvc:interceptors><!--class中写拦截器的全类名-->
        <bean class="com.neuedu.interceptor.Inteceptor1"></bean>

    </mvc:interceptors>

这样在请求后台的响应的时候就会经过拦截器，执行拦截器中的方法。