类与接口的关系

1:类实现接口implements,可以多实现，还可以在继承一个类的同时实现多个接口
2:接口可以继承单个或者多个接口

抽象类与接口的区别

1:成员区别

  • 抽象类：变量，常量；有构造方法但是要通过子类实例化；有抽象方法，也有非抽象方法。
  • 接口：常量默认public static final;抽象方法默认public abstract
    2:设计理念
  • 抽象类：对类抽象，包括属性，行为
  • 接口：对行为抽象
    抽象类实现事物基础实现的功能（共性），接口实现特殊功能
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    public interface SpeakEnglish {
    void speak();
    }
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    public abstract class Person {
    private String name;
    private int age;
    public String getName() {
    	return name;
    }
    public void setName(String name) {
    	this.name = name;
    }
    public int getAge() {
    	return age;
    }
    public void setAge(int age) {
    	this.age = age;
    }
    public Person() {
    	super();
    	// TODO Auto-generated constructor stub
    }
    public Person(String name, int age) {
    	super();
    	this.name = name;
    	this.age = age;
    }
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    public abstract class Player extends Person {

    abstract void study();

    	public Player() {
    		super();
    		// TODO Auto-generated constructor stub
    	}

    	public Player(String name, int age) {
    		super(name, age);
    		// TODO Auto-generated constructor stub
    	}

    }
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    public class BasketballPlayer extends Player implements SpeakEnglish {

    	@Override
    	public void speak() {
    		// TODO Auto-generated method stub
    System.out.println("说英语");
    	}

    	@Override
    	public void eat() {
    		// TODO Auto-generated method stub
    System.out.println("吃篮球餐");
    	}

    	@Override
    	void study() {
    		// TODO Auto-generated method stub
    		System.out.println("学习篮球");
    	}

    	public BasketballPlayer() {
    		super();
    		// TODO Auto-generated constructor stub
    	}

    	public BasketballPlayer(String name, int age) {
    		super(name, age);
    		// TODO Auto-generated constructor stub
    	}

    	@Override
    	public String toString() {
    		return "BasketballPlayer [getName()=" + getName() + ", getAge()=" + getAge() + "]";
    	}
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    public class Test {

    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    BasketballPlayer bp=new BasketballPlayer("张三",30);
    bp.eat();
    bp.study();
    bp.speak();
    System.out.println(bp.toString());
    	}

    }
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    吃篮球餐
    学习篮球
    说英语
    BasketballPlayer [getName()=张三, getAge()=30]