sitemesh 问题解决
项目中加入sitemesh，却不起作用原因：WEB.xml中添加sitemesh支持时有问题，把对sitemesh的添加
<filter><filter-name>struts-cleanup</filter-name><filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class></filter><filter-mapping><filter-name>struts-cleanup</filter-name><url-pattern>/*</url-pattern></filter-mapping>的后面
