问题
I have been learning spring framework for some time.But whenever I look for initialization and destruction callbacks, every example uses ConfigurableApplicationContext instead of ApplicationContext. Can someone explain why?
回答1:
Because all common implementation of ApplicationContext are in fact ConfigurableApplicationContext. Extract from javadoc for ConfigurableApplicationContext :
SPI interface to be implemented by most if not all application contexts.
and
Configuration and lifecycle methods are encapsulated here to avoid making them obvious to ApplicationContext client code. The present methods should only be used by startup and shutdown code
That means that when you use an application context, i.e. get beans from it you only use it as an ApplicationContext but when you manage its life cycle (initialization and destruction) you use methods from ConfigurableApplicationContext
回答2:
ApplicationContext: This the most powerful Container, compare to Bean-factory (Core container).
ConfigurableApplicationContext: One of the implementation of the ApplicationContext container. This container is used for Event Handling propose.
If you implement the following methods and your Bean Class extends the ApplicationListner interface, then when these methods are executed, your Bean will get related Events.
void refresh()
void close();
void shutdown();
来源：https://stackoverflow.com/questions/30861709/configurableapplicationcontext-vs-applicationcontext