Facade Pattern
Provide a unified interface to a set of interfaces in a subsystem.Facade defines a higher-level interface that makes the
subsystem easier to use.(请求一个子体系的外部与其内部的通讯必需通过一个统一的对象进行，门面模式供给一个高层次的接口，使得子体系更容易于应用)Provide a unified interface to
