6、spring拦截器

1.需求：在部分需要判断用户是否存在的情况下访问一些页面，如果用户不是登录状态则需要先登录。

package com.iflysse.bbs.interceptor;

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

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class AuthorInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request,
            HttpServletResponse response, Object handler) throws Exception {
        
        HttpSession session = request.getSession(true);
        if(session.getAttribute("user") == null){
            response.sendRedirect(request.getContextPath() + "/login");
            return false;
        }
        return true;
    }
}

在spring-serlvet.xml中添加：
<!-- 拦截器 -->
    <mvc:interceptors>
        <mvc:interceptor>
　　　　　　<!--访问的路径在/person后的进行拦截-->
            <mvc:mapping path="/person/**" />
            <bean class="com.iflysse.bbs.interceptor.AuthorInterceptor" />
        </mvc:interceptor>
    </mvc:interceptors>