Head First 书中的9条设计原则

1. [封装变化]:找出应用中可能变化需要变化之处,把他们独立出来,不要和那些不需要变化之处的代码混在一起.(Identify the aspects of your application that vary separate them from what the same.)
2. 针对接口编程(Progrma to an interface,not an implementation.)
3. 多用组合少用继承(Favor composition over inheritance.)
4. 为了交互对象之间的松耦合设计而努力!(Strive for loosely coupled designs between objects that interact.)
5. 类应该扩展开放,对修改关闭(Classes should be open for extension but closed for modification.)
6. 要依赖抽象,不要依赖具体类(Depend on abstractions,Do not depend on concrete classes.)
7. 最少知识原则:只和你的密友谈话(Only talk to your friends.)
8. 别打电话给(调用)我,我会打电话给(调用)你(Don't call us,we'll call you.)
9. 一个类应该只有一个引起变化的原因(A class should have only one reason to change.)
10. Add 10,God Bless you and me!Thanks~~