struts2 set struts.devMode to false to disable this message

see http://struts.apache.org/release/2.2.x/docs/devmode.html

And thirdly, perhaps the setting which is less widely known, and therefore a source of much confusion: it will
raise the level of debug or normally ignorable problems to errors. For example: when you
submit a field which cannot be set on an action 'someUnknownField', it will normally be ignored. However, when you're in development mode,
an exception will be thrown, telling you an invalid field was submitted. This is very useful for debugging or testing large forms, but can also be confusing if you're relying on parameters in your request that are not set on the action, but
which you are using directly in your view layer (warning: bad practice, you should always validate input from the web).

这个其实不影响，只是开发模式设置的，你可以在struts.xml设置

<constant name="struts.devMode" value="false“/>

就可以屏蔽掉了