1.接口的概念

当不是所有子类, 而是多个子类都包含一个方法时, 为了代码书写规范性, 可以用自定义的接口来统一该方法的书写规范. 所以接口可以看作是一种书写规则.

接口是对行为的抽象

抽象类一般是书写在父类当中, 接口是单独书写的, 不是一种类

2.接口的定义和使用

3.接口中成员的特点

4.接口和类的关系

当一个类实现多个接口, 并且多个接口中有重名的方法时, 只用实现一个接口中的同名方法.(也就是说每个方法只实现一次)

若类implements子接口, 那么就需要重写所有的抽象方法(包括父接口方法)

5.接口和抽象类的综合案例

package cn.ncepu.demo1.a02abstrctdemo2;

public abstract class Person {
    private String name;
    private int age;

    public Person() {
    }

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public abstract void work();

    /**
     * 获取
     * @return name
     */
    public String getName() {
        return name;
    }

    /**
     * 设置
     * @param name
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * 获取
     * @return age
     */
    public int getAge() {
        return age;
    }

    /**
     * 设置
     * @param age
     */
    public void setAge(int age) {
        this.age = age;
    }

    public String toString() {
        return "Person{name = " + name + ", age = " + age + "}";
    }
}


package cn.ncepu.demo1.a02abstrctdemo2;

public class PingPong extends Person implements Speak{
    public PingPong() {
    }

    public PingPong(String name, int age) {
        super(name, age);
    }

    @Override
    public void work() {
        System.out.println("学打乒乓球");
    }

    @Override
    public void speak() {
        System.out.println("说英语");
    }
}

package cn.ncepu.demo1.a02abstrctdemo2;

public class Basketball extends Person{
    public Basketball() {
    }

    public Basketball(String name, int age) {
        super(name, age);
    }

    @Override
    public void work() {
        System.out.println("学打篮球");
    }
}


package cn.ncepu.demo1.a02abstrctdemo2;

public class PingPongCoach extends Person implements Speak{
    public PingPongCoach() {
    }

    public PingPongCoach(String name, int age) {
        super(name, age);
    }

    @Override
    public void work() {
        System.out.println("教打乒乓球");
    }

    @Override
    public void speak() {
        System.out.println("说英语");
    }
}

package cn.ncepu.demo1.a02abstrctdemo2;

public class BasketballCoach extends Person{
    public BasketballCoach() {
    }

    public BasketballCoach(String name, int age) {
        super(name, age);
    }

    @Override
    public void work() {
        System.out.println("教打篮球");
    }
}


package cn.ncepu.demo1.a02abstrctdemo2;

public interface Speak {
    public abstract void speak();
}


package cn.ncepu.demo1.a02abstrctdemo2;

public class Test {
    public static void main(String[] args) {
        PingPong pingPong = new PingPong("乒乓球运动员", 18);
        Basketball basketball = new Basketball("篮球运动员", 20);

        PingPongCoach pingPongCoach = new PingPongCoach("乒乓球教练", 35);
        BasketballCoach basketballCoach = new BasketballCoach("篮球教练", 38);

        pingPong.work();
        basketball.work();
        pingPongCoach.work();
        basketballCoach.work();

        pingPongCoach.speak();
        pingPong.speak();
    }
}