spring设置拦截器

1. 拦截器(拦截都是控制层的地址。 filter: )
   1. 创建一个类 实现接口 HandlerInterceptor

      package com.zhiyou100.wyf.interceptor;
      
      import javax.servlet.http.HttpServletRequest;
      import javax.servlet.http.HttpServletResponse;
      
      import org.springframework.web.servlet.HandlerInterceptor;
      import org.springframework.web.servlet.ModelAndView;
      
      public class MyInterceptor implements HandlerInterceptor{
      
          @Override
          public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
                  throws Exception {
              System.out.println("结束");
          }
      
          @Override
          public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
                  throws Exception {
              
              System.out.println("预备");
              
          }
      
          @Override
          public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
              Object name = request.getSession().getAttribute("name");
              if(name!=null) {
                  return true;
              }else {
                  response.sendRedirect("../denglu.jsp");
                  return false;
              }
          }
          
          
      
      }

   2. 重写接口的中方法
   3. 把创建的类配置到springmvc文件中。

    <!-- 配置拦截器 -->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/user/**"/>
            <mvc:exclude-mapping path="/user/login"/>
            <mvc:exclude-mapping path="/user/register"/>
            <mvc:exclude-mapping path="/user/stu1"/>
            <bean class="com.zhiyou100.wyf.interceptor.MyInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>