摘要： The Single-Responsibility Principle (SRP)A class should have only one reason to change.单一职责原则（SRP）一个类应该仅有一个引起它变化的原因。The Open/Closed Principle (OCP)Software entities (classes, modules, functions, etc.) should be open for extension but closed for modification.开放封闭原则（OCP）软件实体（类，模块，函数等等）应该是对扩展开放的，对修改封闭的 阅读全文