2021-04-25

Uncle:

public class Uncle {
    private  String name ;
    private  int age ;

    public  Uncle(){

    }
    public  Uncle(String name , int age){
        this.name = name ;
        this.age = age ;
    }
    public void fahongbao(){
        System.out.println("发红包");
    }

    public String getName(){
        return  name ;
    }

    @Override
    public String toString() {
        return "Uncle{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public int getAge() {
        return age;
    }

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

    public void setAge(int age) {
        this.age = age;
    }
}

UncleOne:

public class UncleOne extends  Uncle {
    public void faHongbao(){
        System.out.println("发红包");
    }
    public void songyan(){
        System.out.println("送烟");
    }
}

UncleTwo :

public class UncleTwo extends  Uncle {
    public void faHongbao(){
        System.out.println("发红包");
    }
}

Dome01:

public class Dome01 {
    public static void main(String[] args) {
        //多态
        UncleOne dajiu = new UncleOne();
        dajiu.faHongbao();
        UncleTwo uncleTwo = new UncleTwo() ;
        uncleTwo.faHongbao();

        Uncle dajiu1 = new UncleOne() ;
        dajiu1.fahongbao();
        //dajiu1.songyan     //会报错 子类独有的方法在发生向上转型的时候无法在父类中使用
        UncleOne temp = (UncleOne) dajiu1 ;
        temp.songyan();

        Uncle erjiu = new UncleTwo() ;
        erjiu.fahongbao();

        //向下转型
        Uncle uncleTwo1 = new UncleTwo() ;
        UncleTwo temp1 = (UncleTwo) uncleTwo;
        temp.faHongbao();
    }
}

Dome02:

public class Dome02 {
    public static void main(String[] args) {
        Uncle uncle1= new UncleOne() ;
        Uncle uncle2 = new UncleTwo() ;
        if (uncle1 instanceof  UncleOne){
            UncleOne u1 = (UncleOne) uncle1 ;
            u1.fahongbao();
        }
        if (uncle2 instanceof  UncleTwo){
            UncleTwo u2 = (UncleTwo)  uncle2 ;
            u2.faHongbao();
        }
    }
}