Why we can't use execAndWait interceptor using ServletActionContext?

Question

I have to use loading bar on selected actions in Struts2, & am using ServletActionContext, but getting NullPointerException.

ActionContext.getContext().get(org.apache.struts2.StrutsStatics.HTTP_REQUEST);

If I remove execAndWait interceptor from xml configuration file, it works fine.

Some people suggested me to use SessionAware. Why so ?

Is there any solution ?

Answer 1

The ActionContext is ThreadLocal and it doesn't have a request object when you run a background thread via execAndWait interceptor.

If you use SessionAware, then you should have servletConfig interceptor on the stack to be able to set the session object to your action before the action is executed.

Solution: if you can get ServletRequestAware to set a request object to the action and use servletConfig interceptor prior the execAndWait interceptor in the stack. If you need to create a custom stack you should keep the order.