springMVC的拦截器配置

package com.imooc.core;

import com.imooc.bean.User;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

public class LoginInterceptor implements HandlerInterceptor {


    //在业务处理器被调用前的方法，若是返回false则不会继续进入业务处理器
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        User user = (User)request.getSession().getAttribute("session_user");
        if(user==null) {
            response.sendRedirect(request.getContextPath()+"/login");
            return false;//会终止所有的请求

        }
        return true;
    }

    //在业务处理器被调用后，dispatcher响应客户端前的方法，一般用于生成日志文件时调用
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    //dispatcher响应客户端后的方法，一般用于资源的清理
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

    <!-- 拦截器的注册 -->
    <mvc:interceptors>
        <mvc:interceptor>
             <!--**表示往后的所有子目录也包括进来-->
            <mvc:mapping path="/user/**"></mvc:mapping>
            <!--exclude-mapping在所有拦截中进行排除，一般在通配符会有意义。-->
            <!--即以下的方法不会被拦截-->
            <mvc:exclude-mapping path="/user/updatepwd"></mvc:exclude-mapping>
            <mvc:exclude-mapping path="/user/updatebackground/*"></mvc:exclude-mapping>
            <!--填写之前配置好的拦截器-->
            <bean class="com.imooc.core.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>

    <!-- 拦截器的注册 -->
    <mvc:interceptors>

        <!--先注册先执行-->
        <mvc:interceptor>
            <mvc:mapping path="/user/**"/>
            <bean class="com.imooc.core.LogInterceptor"></bean>
        </mvc:interceptor>

        <mvc:interceptor>
            <mvc:mapping path="/user/**"></mvc:mapping>
            <!--exclude-mapping在所有拦截中进行排除，一般在通配符会有意义。-->
            <mvc:exclude-mapping path="/user/updatepwd"></mvc:exclude-mapping>
            <mvc:exclude-mapping path="/user/updatebackground/*"></mvc:exclude-mapping>
            <bean class="com.imooc.core.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>