练习10.9-2

父类

package hello;

public class Yinshuiji {//创建父类饮水机
    
    
    public Yinshuiji(String pinpai,int shuiliang){//构造方法
        
        this.pinpai = pinpai;//品牌
        this.shuiliang = shuiliang;//当前水量
        System.out.println("饮水机品牌是：" +pinpai + ", 当前水量为" +shuiliang );
        
    }
    
    String pinpai;
    int shuiliang;
    int shengyushuiliang;
    
    //方法一：接水
    public void jieshui(int jieshuiliang){
        
        if(jieshuiliang > shuiliang){
            System.out.println("已经没水了");
        }
        else
        {
            shengyushuiliang = shuiliang - jieshuiliang;
            System.out.println("饮水机剩余水量 = " + shengyushuiliang);
        }
            
    }
    
    //方法二：烧水
    public void shaoshui(int time){
        
        int shuiwen = 20;
        shuiwen = shuiwen + time * 10;
        if(shuiwen > 100)
        {
            System.out.println("水已经开了");
        }
        else
        {
            System.out.println("现在水温 = " + shuiwen);
        }
        
    }
    

}

子类

package hello;

public class Dagonglvysj extends Yinshuiji {//创建子类大功率饮水机

    public Dagonglvysj(String pinpai, int shuiliang) {
        super(pinpai, shuiliang);
        // TODO Auto-generated constructor stub
    }
    
    //重写父类方法二
    public void shaoshui(int time)
    
    {
        int shuiwen = 20;
        shuiwen = shuiwen + time * 20;
        if(shuiwen > 100)
        {
            System.out.println("水已经开了");
        }
        else
        {
            System.out.println("现在水温 = " + shuiwen);
        }
        
    }

}

向上转型

package hello;

public class Test {

    public static void main(String[] args){
        
        Yinshuiji ysj = new Dagonglvysj("美帝",50);//向上转型
        
        ysj.shaoshui(2);//调用子类重写的方法二