java abstract抽象类学习-优快云博客

本文通过一个生动的例子介绍了Java中抽象类的概念及使用方法。通过定义一个抽象类“水果”，并以此为基础创建具体的子类如“苹果”和“梨”，展示了如何实现多态性和继承特性。

java抽象类
java abstract class

有时候，我们需要用到抽象类。比如我们想买水果，但是不确定买的是苹果还是香蕉
Sometimes, we want to abstract a class.For example, We want buy some fruits,but we are not sure we buy apple or pear.

我们抽象出一个类叫水果
Now we can abstract a class named Fruit

水果就作为了一个抽象类和一个父亲类
Fruit is a abstract class and it is a father class.

苹果和梨就作为子类
Apples and pears fruit is child class

注意：我们不能获得一个抽象类的对象 new Fruit() 会发生错误。
note: can not get a new abstract class new Fruit() is wrong

abstract father class

public abstract class Fruit {
	public String getColor(String color){
		return color;
	}

	public String getWeight(String weight){
		return weight;
	}
}

child class


public class Apple extends Fruit {

	public String getColor(String color){

		System.out.println(‘‘color is ‘‘ + color);

		return color;

	}



	public String getWeight(String weight){

		System.out.println(‘‘weight is ‘‘ + weight);

		return weight;

	}



	public static void main(String[] args){

		Fruit f = new Apple();

		//Fruit f = new Fruit();   can not get a new abstract class  new Fruit() is wrong

		f.getColor(‘‘red‘‘);

	}

}

首发于 http://java-er.com - http://java-er.com/blog/java-abstract/