2013-04-17 未登录，不允许访问项目文件夹内的页面，那如何判断是否登录呢？ 下面向大家详细介绍spring mvc Session拦截器的使用，本文以登录为例，未登录无权限访问项目内页面，session为空时返回项目首页。 代码如下：

如有访客不明白的可以给我留言，我会给大家满意的解决方法…… 

[html] package com.sundear.sundearemm.interceptor;    import com.sundear.sundearemm.model.User;  import java.util.logging.Level;  import java.util.logging.Logger;  import javax.servlet.http.HttpServletRequest;  import javax.servlet.http.HttpServletResponse;  import org.springframework.web.servlet.HandlerInterceptor;  import org.springframework.web.servlet.ModelAndView;    /**   *   * @author yh   */  public class SessionInterceptor implements HandlerInterceptor {        private Logger logger =           Logger.getLogger(SessionInterceptor.class.getName());        @Override      public boolean preHandle(HttpServletRequest hsr, HttpServletResponse hsr1, Object o) throws Exception {          User user=(User) hsr.getSession().getAttribute("LoginUser");          if(user==null){              logger.log(Level.INFO, "user not login");              hsr1.sendRedirect("/SundearEmm");              return false;          }          return true;      }        @Override      public void postHandle(HttpServletRequest hsr, HttpServletResponse hsr1, Object o, ModelAndView mav) throws Exception {      }        @Override      public void afterCompletion(HttpServletRequest hsr, HttpServletResponse hsr1, Object o, Exception excptn) throws Exception {      }  }  package com.sundear.sundearemm.interceptor; import com.sundear.sundearemm.model.User; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; /**  *  * @author yh  */ public class SessionInterceptor implements HandlerInterceptor {     private Logger logger = Logger.getLogger(SessionInterceptor.class.getName());     @Override     public boolean preHandle(HttpServletRequest hsr, HttpServletResponse hsr1, Object o) throws Exception {         User user=(User) hsr.getSession().getAttribute("LoginUser");         if(user==null){             logger.log(Level.INFO, "user not login");             hsr1.sendRedirect("/SundearEmm");             return false;         }         return true;     }     @Override     public void postHandle(HttpServletRequest hsr, HttpServletResponse hsr1, Object o, ModelAndView mav) throws Exception {     }     @Override     public void afterCompletion(HttpServletRequest hsr, HttpServletResponse hsr1, Object o, Exception excptn) throws Exception {     } }仅这些还不够，我们还需要修改spring mvc的配置文件dispatcher-servlet.xml,加入拦截器代码如下：   [html] <!-- interceptors -->      <mvc:interceptors >              <mvc:interceptor>                  <mvc:mapping path="/group/*" />              <mvc:mapping path="/user/*"/>              <mvc:mapping path="/subscribe/*"/>              <mvc:mapping path="/recipient/*"/>              <mvc:mapping path="/mail/*"/>              <bean class="com.sundear.sundearemm.interceptor.SessionInterceptor"></bean>              </mvc:interceptor>          </mvc:interceptors>  <!-- interceptors -->     <mvc:interceptors >            <mvc:interceptor>                <mvc:mapping path="/group/*" />             <mvc:mapping path="/user/*"/>             <mvc:mapping path="/subscribe/*"/>             <mvc:mapping path="/recipient/*"/>             <mvc:mapping path="/mail/*"/>             <bean class="com.sundear.sundearemm.interceptor.SessionInterceptor"></bean>            </mvc:interceptor>        </mvc:interceptors>