SpringMVC之拦截器的的配置和使用

拦截器与过滤器的区别：拦截器只能拦截controller的请求，过滤器可以过滤所有请求

（1）实现HandlerInterceptor接口

　　　在执行控制器中的方法之前执行preHandle（）中的方法

package com.eu.weh.web;

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;

import com.eu.weh.bean.User;

/**
 * 
 * @ClassName: LoginInterceptor
 * @Description: 登录拦截器
 * @author Administrator
 * @date 2019年4月29日 上午10:31:25
 *
 */
public class LoginInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        
        //判断当前用户是否已经登录
        HttpSession session = request.getSession();
        User loginUser = (User) session.getAttribute("dbUser");
        if (loginUser == null) {
            String path = session.getServletContext().getContextPath();
            response.sendRedirect(path+"/login");
            return false;
        }else {
            return true;
        }
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        
    }

}

（2）SpringMVC配置文件

<mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**" />
            <mvc:exclude-mapping path="/login" />
            <mvc:exclude-mapping path="/doAJAXlogin" />
            <mvc:exclude-mapping path="/bootstrap/**" />
            <mvc:exclude-mapping path="/css/**" />
            <mvc:exclude-mapping path="/fonts/**" />
            <mvc:exclude-mapping path="/img/**" />
            <mvc:exclude-mapping path="/jquery/**" />
            <mvc:exclude-mapping path="/layer/**" />
            <mvc:exclude-mapping path="/script/**" />
            <mvc:exclude-mapping path="/ztree/**" />
            <bean class="com.eu.weh.web.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>