在struts2.3.16.1下，web.xml中使用
… <filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.FilterDispatcher </filter-class>
会出现
***********************************************************************
* WARNING!!! *
* *
* >>> FilterDispatcher <<< is deprecated! Please use the new filters! *
* *
* This can be a source of unpredictable problems! *
* *
* Please refer to the docs for more details! *
* http://struts.apache.org/2.x/docs/webxml.html *
* *
***********************************************************************
原因在于:
Class FilterDispatcher Deprecated. Since Struts2.3.16.1, use StrutsPrepareAndExecuteFilter instead or StrutsPrepareFilterand StrutsExecuteFilter if needing using the ActionContextCleanUp filter in addition to this one..即，从Struts 2.1.3起已被标注为过时的，改用StrutsPrepareAndExecuteFilter
解决方法，将web.xml上述代码改为：
…
<filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter </filter-class> </filter>
来自：http://www.cnblogs.com/babybluevino/