这是一本讲述c#设计模式的书籍，比如三层架构设计模式，并通过一个实例讲述了如何运用这种模式来设计系统-This is on a c# design pattern books, such as three-tier architecture model, and through an example about how to use this model to design the system

java三层架构实现购物车实例，大家可以参考一下-three-tier architecture to achieve java shopping cart instance, we can refer to