1.写一个宠物类Pet,属性:id name health love;重写父亲类toString()方法 2.两个子类狗类和猫类,狗狗有品种(strain),猫类有爱好(hobby),重写父类TOString()方法 3.宠物饿了,需要主人给宠物喂食,狗狗吃狗粮,猫咪吃小鱼.吃完之后健康值狗狗增加3,猫咪增加5

好的，这是三个问题，我分别回答：

1. 宠物类Pet的代码如下：

public class Pet {
    protected int id;
    protected String name;
    protected int health;
    protected int love;

    public Pet(int id, String name, int health, int love) {
        this.id = id;
        this.name = name;
        this.health = health;
        this.love = love;
    }

    @Override
    public String toString() {
        return "Pet{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", health=" + health +
                ", love=" + love +
                '}';
    }
}

2. 狗类和猫类的代码如下：

public class Dog extends Pet {
    private String strain;

    public Dog(int id, String name, int health, int love, String strain) {
        super(id, name, health, love);
        this.strain = strain;
    }

    @Override
    public String toString() {
        return "Dog{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", health=" + health +
                ", love=" + love +
                ", strain='" + strain + '\'' +
                '}';
    }
}

public class Cat extends Pet {
    private String hobby;

    public Cat(int id, String name, int health, int love, String hobby) {
        super(id, name, health, love);
        this.hobby = hobby;
    }

    @Override
    public String toString() {
        return "Cat{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", health=" + health +
                ", love=" + love +
                ", hobby='" + hobby + '\'' +
                '}';
    }
}

3. 给宠物喂食的代码如下：

public class Main {
    public static void main(String[] args) {
        Dog dog = new Dog(1, "旺财", 80, 90, "哈士奇");
        Cat cat = new Cat(2, "咪咪", 70, 80, "玩线球");

        System.out.println(dog);
        System.out.println(cat);

        feed(dog, "狗粮");
        feed(cat, "小鱼");

        System.out.println(dog);
        System.out.println(cat);
    }

    public static void feed(Pet pet, String food) {
        if (pet instanceof Dog && food.equals("狗粮")) {
            pet.health += 3;
        } else if (pet instanceof Cat && food.equals("小鱼")) {
            pet.health += 5;
        }
    }
}

注意，这里的feed方法中，我们使用了instanceof运算符来判断宠物是狗还是猫。当宠物是狗且喂食的是狗粮时，健康值增加3；当宠物是猫且喂食的是小鱼时，健康值增加5。最后我们打印出喂食后的宠物信息。