拦截器

1.拦截器作用

　　拦截控制方法的执行

2.实现

package com.cj.rest.interceptors;

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

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

@Component
public class FirstInterceptors implements HandlerInterceptor {

    //    控制器执行之前
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("FirstInterceptors--preHandle");
        return true;
    }
    //    控制器执行之后
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("FirstInterceptors--postHandle");

    }
    //    视图渲染完成之后
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("FirstInterceptors--afterCompletion");

    }
}

xml

 <mvc:interceptors>
-        <bean class="com.cj.rest.interceptors.FirstInterceptors"></bean>-->
-        <ref bean="firstInterceptors"/>-->
     <mvc:interceptor>
         <mvc:mapping path="/**"/> //拦截所有
         <mvc:exclude-mapping path="/"/>
         <ref bean="firstInterceptors"/>
     </mvc:interceptor>
 </mvc:interceptors>