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>