Struts 2 on Google app engine. problem

I use struts2 in google app engine I had an error with my application.

result 'null' not found 

But when I created listener OGNL this error is not displaying.

http://whyjava.wordpress.com/2009/08/30/creating-struts2-application-on-google-app-engine-gae/

to resolve this probl开发者_如何转开发em I created an ServletContextListner which will set OGNL security manager to null when the context is initialized. when I created this listener this error is not displaying.

But now I have blank page without any text in my browser. When I call to any page, nothing display. Why? Please, help me.

Empty pages in Struts2 are often related to validation. Default stack includes validation interceptor which tries to validate all methods except for input,back,cancel,browse:

<interceptor-ref name="validation">
    <param name="excludeMethods">input,back,cancel,browse</param>
</interceptor-ref>

Try to call your action with _input appendix (YourAction_input.action) or add execute method to the list of excluded methods for validation interceptor.