Java基础学习-面向对象三大特征之一：封装

package fengzhuang;

public class Cat {
    String name;
    private int age;

    public Cat(){

    }
    public void eat(){
        System.out.println("猫吃鱼");
    }
    public void setAge(int age){
        if(age>0){
            this.age=age;
        }else{
            System.out.println("年龄不规范");
        }
    }
    public void show(){
        System.out.println(this.name);
        System.out.println(this.age);
    }
}

package fengzhuang;

public class CatDemo {
    public static void main(String[] args) {
        Cat cat = new Cat();
        cat.name="毛毛";
        cat.setAge(-28);
        cat.eat();
        cat.show();
    }
}