1. 分析宠物店种的类与方法

宠物：狗，猫，鸭子
宠物属性：有名字，健康值
狗类的属性：狗还有种类
方法：都会叫，都会简绍自己

鉴于它们都会叫和简绍，所以可以用接口或者抽象类来实现方法

2.代码如下：

定义抽象类，内含声音方法,j简绍方法

package petshop;

public abstract class  Function {
    abstract void sound() ;
    abstract void speak();
}

定义宠物类，内含宠物姓名，宠物健康值

package petshop;

public class Pets extends Function {
    private String name ;
    private int healthIndex;

    public Pets() {
        this("无名氏",80);
    }

    public Pets(String name, int healthIndex) {
        this.name = name;
        this.healthIndex = healthIndex;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getHealthIndex() {
        return healthIndex;
    }

    public void setHealthIndex(int healthIndex) {
        this.healthIndex = healthIndex;
    }

    @Override
    void sound() {

    }

    @Override
    void speak() {
        System.out.println("我的名字是："+this.name+"我的健康值是："+this.healthIndex);
    }
}

定义狗类，内包含狗类别和继承父类宠物类

package petshop;

public class Dog extends Pets {
    private String  kinds;

    public Dog() {
        super();
        this.kinds = "品种未知";
    }

    public Dog(String name, int healthIndex, String kinds) {
        super(name, healthIndex);
        this.kinds = kinds;
    }

    public String getKinds() {
        return kinds;
    }

    public void setKinds(String kinds) {
        this.kinds = kinds;
    }

    @Override
    public void sound() {
        System.out.println("汪汪汪");
    }

    @Override
    public String toString() {
        return super.toString()+"，我的品种是："+kinds;
    }
}

Duck 类

package petshop;

public class Duck extends Pets {
    public Duck() {
    }

    public Duck(String name, int healthIndex) {
        super(name, healthIndex);
    }

    @Override
    public void sound() {
        System.out.println("嘎嘎嘎");
    }
}

Cat类

package petshop;

public class Cat extends Pets {
    public Cat() {
    }

    public Cat(String name, int healthIndex) {
        super(name, healthIndex);
    }

    @Override
    public void sound() {
        System.out.println("喵喵喵");
    }
}

PetsShop类 其中包括商店进宠物，还有随机给顾客简绍宠物

package petshop;

import java.util.Random;
import java.util.Scanner;

public class PetShop {
    static Pets pet[] = new Pets[3];
    static PetShop petShop = new PetShop();

    static Scanner scanner = new Scanner(System.in);

    static String name[] = new String[3];
    static int healthIndex[] = new int[3];
    static String kinds[] = new String[3];

    public static void main(String[] args) {
        String str = new String();
//进货
        for (int i = 0; i < 3; i++) {
            System.out.println("请输入Dog/Cat/Duck");
            str = scanner.next();
            if (str.equalsIgnoreCase("dog")) {
                System.out.println("请输入第" + (i + 1) + "只宠物的名字");
                name[i] = scanner.next();
                System.out.println("请输入第" + (i + 1) + "只宠物的健康指数");
                healthIndex[i] = scanner.nextInt();
                System.out.println("请输入第" + (i + 1) + "只宠物的种类");
                kinds[i] = scanner.next();
                petShop.pet[i] = new Dog(name[i], healthIndex[i], kinds[i]);
            } else if(str.equalsIgnoreCase("duck")){
                System.out.println("请输入第" + (i + 1) + "只宠物的名字");
                name[i] = scanner.next();
                System.out.println("请输入第" + (i + 1) + "只宠物的健康指数");
                healthIndex[i] = scanner.nextInt();
                petShop.pet[i] = new Duck(name[i], healthIndex[i]);
            }else if (str.equalsIgnoreCase("cat")){
                System.out.println("请输入第" + (i + 1) + "只宠物的名字");
                name[i] = scanner.next();
                System.out.println("请输入第" + (i + 1) + "只宠物的健康指数");
                healthIndex[i] = scanner.nextInt();
                petShop.pet[i] = new Cat(name[i], healthIndex[i]);
            }else {
                System.out.println("输入错误！！");
            }

        }
            for (int i = 0; i < 3; i++) {
            //随机选择宠物
            int index = new Random().nextInt(petShop.pet.length);
            Pets pet = petShop.pet[index];

            //宠物开始自我介绍
            pet.speak();

            //我给你唱歌
            pet.sound();
        }
    }
}

3.接口实现

将抽象类换成接口，方法不用实现，谁调用接口谁实现方法，可以将sound（）与speak（）分成两个接口，使其复用性更强。