<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>
<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>
该filter清除缓存。在做上传文件时，要在web.xml中增加ActionContextCleanUp这个filter，否则会发生第一次上传取不到文件的情况。
原帖地址:http://blog.sina.com.cn/s/blog_5bd6b45101012i74.html
