各位技术大牛，请问我struts2配置文件正确吗
请问struts2 org.apache.struts2.dispatcher.ActionContextCleanUp有何用



<? xml version="1.0" encoding="UTF-8" ?> 
< web-app id ="WebApp_9" version ="2.4" 
  xmlns ="http://java.sun.com/xml/ns/j2ee" 
  xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation ="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" > 

  < display-name > Struts 2 Fileupload </ display-name > 

  < filter > 
  < filter-name > struts-cleanup </ filter-name > 
  < filter-class > 
  org.apache.struts2.dispatcher.ActionContextCleanUp
  </ filter-class > 
  </ filter > 
   
  < filter > 
  < filter-name > struts2 </ filter-name > 
  < filter-class > 
  org.apache.struts2.dispatcher.FilterDispatcher
  </ filter-class > 
  </ filter > 
   
  < filter-mapping > 
  < filter-name > struts-cleanup </ filter-name > 
  < url-pattern > /* </ url-pattern > 
  </ filter-mapping > 

  < filter-mapping > 
  < filter-name > struts2 </ filter-name > 
  < url-pattern > /* </ url-pattern > 
  </ filter-mapping > 

  < welcome-file-list > 
  < welcome-file > index.html </ welcome-file > 
  </ welcome-file-list > 

</ web-app >

------解决方案--------------------
ctionContextCleanUp 清除Stack Context和ValueStack中的值

过滤器顺序：
（1）ActionContextCleanUp过滤器。
（2）SiteMesh核心过滤器。
（3）FilterDispatcher过滤器。