封装与隐藏

 

/**
 * 封装和隐藏
 */

public class fengzhuang {
    public static void main(String[] args) {
        Animal animal =new Animal();
        animal.name="黑子";
//        animal.age=2;
        animal.setAge(30);
//        animal.legs=4;
//        animal.eat();
        animal.setLegs(4);
        animal.show();

        System.out.println(animal.getLegs());
    }
}
    class Animal{
        String name;
       private int age;
       private int legs;//腿的个数
        //对象属性的设置
        public void setLegs(int i){
            if (i>=0 && i%2==0){
                legs =i;
            }else {
                legs=0;
            }
        }
        //对象属性的获取
        public int getLegs(){
            return legs;
        }
        public int getAge(){
            return age;
        }
        public void setAge(int a){
            age=a;
        }
        public void eat(){
            System.out.println("动物吃东西");
        }
        public void show(){
            System.out.println("name = "+name+",age = "+age+",S = "+legs);
        }
}

 

权限修饰符

return 可以用于结束方法

 

 

public class Person {
    private int age;
//    public void setAge(int age) {
//        if (age>0&&age<130){
//            this.age=age;
//        }else {
//            System.out.println("年龄输入有误");
//        }
//    }
    public void setAge(int age){
        if (age<0||age>130){
            System.out.println("年龄输入错误");
            return;
        }
        this.age=age;
    }
    public int getAge(){
        return age;
    }
}



public class PersonText {
    public static void main(String[] args) {
        Person pe =new Person();
        pe.setAge(190);
        System.out.println(pe.getAge());
    }
}