Single Responsibility Principle 类的设计趋向于:Use Case Diagram --> (derived) --> Detail Open-Closed Principle /* Software entities should be open for extension, but closed for modification */ 反面例子:Dependency: 作为参数,作为局部变量,调用静态方法. 改进方式:增加抽象类或者接口,以及set方法. Li…