1.需求 ：java编写一个宠物类Pet，属性: id,name,health,love ;重写父类toString()方法 o两个子类狗狗和猫类，狗狗有品种(strain),猫类有爱好(hobby),重写父类toString()方法 o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，下面是代码实现：

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

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

    public void eat() {
        System.out.println(name + " is eating.");
        if (this instanceof Dog) {
            health += 3;
        } else if (this instanceof Cat) {
            health += 5;
        }
    }

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

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=" + getId() +
                ", name='" + getName() + '\'' +
                ", health=" + getHealth() +
                ", love=" + getLove() +
                ", 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=" + getId() +
                ", name='" + getName() + '\'' +
                ", health=" + getHealth() +
                ", love=" + getLove() +
                ", hobby='" + hobby + '\'' +
                '}';
    }
}

以上代码定义了Pet类和两个子类Dog和Cat。Pet类中定义了id、name、health、love四个属性和eat()方法。eat()方法用于宠物吃东西，根据宠物类型不同，增加健康值也不同。Dog类和Cat类分别继承了Pet类，Dog类中定义了strain属性，Cat类中定义了hobby属性。同时，两个子类分别重写了父类的toString()方法，用于输出宠物的属性。