什么是面向对象
- 面向对象编程（oop）
- 面向对象编程的本质是以类的形式组织代码，以对象的形式组织（封装）数据
[En]
The essence of object-oriented programming is to organize code in the form of classes and organize (encapsulate) data in the form of objects*
- 抽象
- 三大特征：封装、继承、多态
- 从认识论的角度来看，课前有对象。物体是具体的东西。类是抽象的，对对象是抽象的
[En]
From the perspective of epistemology, there are objects before classes. An object is a concrete thing. Class is abstract and abstract to objects*
- 从代码运行角度考虑是先有类后有对象。类是对象的模板
回顾方法及加深
运用实例1
```
public class FangFa {
//mian方法
public static void main(String[] args) {
}