说明：  封装给对象提供了隐藏内部特性和行为的能力。对象提供一些能被其他对象访问的方法来改 变它内部的数据。在 Java 当中，有 3 种修饰符： public， private 和 protected。每一种修饰符 给其他的位于同一个包或者不同包下面对象赋予了不同的访问权限。 下面列出了使用封装的一些好处
(Encapsulation provides objects with the ability to hide internal features and behaviors. Object provides methods that can be accessed by other objects to change Change its internal data. In Java, there are three modifiers: public, private, and protected. Every modifier Different access rights are given to other objects under the same package or different packages. Some of the benefits of using encapsulation are listed below)