因为在使用在线编辑器Fckeditor的上传图片的时候会跳出
Security error. You probably don't have enough permissions to upload. Please check your server
还有file upload error num 203
后来才知道和Struts2.0的过滤冲突了
在网络上查找了下别人是这么说的：struts2对request进行了封装，所以当fck的request.getinputStream的时候就会出错.修改的方法就是对filtermapping的路径进行修改。
然后对web.XML修改下就可以了
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<welcome-file-list>