servlet：监听器

1，页面：

2，java：

3.web.xml配置:

 <servlet>
  	<servlet-name>logoutServlet</servlet-name>
  	<servlet-class>com.java1234.web.LogoutServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>logoutServlet</servlet-name>
  	<url-pattern>/logout</url-pattern>
  </servlet-mapping>
  
  <listener>
  	<listener-class>
  		com.java1234.listener.SessionAttributeListener
  	</listener-class>
  </listener>