问题
Can any one please describe me when the objects of ActionMapper, ActionProxy, ActionInvocation, ActionContext are created in a Struts2 application. As I am new to Struts2 framework, I am very much confused about the scopes of these objects.
回答1:
The ActionMapper is created on startup, it has a singleton scope.
The ActionContext is created by the Dispatcher in preparing an action to execute, it's ThreadLocal, and it doesn't have any scope.
When action is executing the ActionInvocation and ActionProxy are created that also don't have a scope.
You can see this on a big picture of Struts2 architecture.
来源：https://stackoverflow.com/questions/26202105/scopes-of-actionmapper-actionproxy-actioninvocation-actioncontext-objects-in