主要考察的是资源池的设计和实现， Domain Model比较简单，仅用于测试资源池，因此IDL也仅仅实现基本存取功能。本资源池的设计主要参考Object Resource Pooling这篇文章中介绍的基本框架-mainly to study the resource pool design and implementation, Domain Model relatively simple. only resource pool for testing, IDL has access onl