1 aop: Aspect Oriented (aspect) programming extension does not modify the source code to achieve
2 AOP taken transverse extraction mechanism replacing the traditional longitudinal succession repetitive coding system
3 aop implemented underlying dynamic proxies
(1) the first case, there is an interface, the interface to create a proxy object class dynamic proxies
(2) the second case, there is no interface, the proxy object subclass dynamic proxy class is created