有些人已经解决你的问题了。在本章，你将学到为何（以及如何）

利用其他开发人员的经验与智慧。他们遭遇过相同的问题，也顺利地解决过这些

问题。本章结束前，我们会看看设计模式的用途与优点，再看一些关键的OO设计

原则，并通过一个实例来了解模式是如何运作。使用模式最好的方式是：“把模

式装进脑子里，然后在你的设计和已有的应用中，寻找何处可以使用它们。”以

往是代码复用，现在是经验复用。-Some people have solved your problem. In this chapter, you will learn why (and how) to take advantage of another developer' s experience and wisdom. They encountered the same problem, and also successfully solved these problems. Before the end of this chapter, we will see if the uses and benefits of design patterns, look at some of the key principles of OO design mode and an example to understand how it works. Usage patterns, the best way is: " mode put into his mind, and then you design and existing applications to find where to use them."　Past code reuse, now is experience multiplexing.