ConcreteCompenent
+ operation()
<interface>Compenent
operation()
经典案例javax.servlet.http.HttpServletRequestWrapperjavax.servlet.http.HttpServletResponseWrapper
以设计模式（装饰器模式）为例，展示类图的画法装饰器：在不改变原有对象类基础上，增加额外的功能
ConcreteDecorator2
+ConcreteDecorator2(Compenent)+ operation()
<abstract>Decorator
compenent:Compenent
client
main(args)
ConcreteDecorator1
+ ConcreteDecorator1(Compenent)+ operation()
main(){ Component component= new ConreteDecorator1( new ConreteDecorator2(new ConcreteComponent())); component.operation();}
