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.