练习10.9-2

父类

 1 package hello;
 2 
 3 public class Yinshuiji {//创建父类饮水机
 4     
 5     
 6     public Yinshuiji(String pinpai,int shuiliang){//构造方法
 7         
 8         this.pinpai = pinpai;//品牌
 9         this.shuiliang = shuiliang;//当前水量
10         System.out.println("饮水机品牌是：" +pinpai + ", 当前水量为" +shuiliang );
11         
12     }
13     
14     String pinpai;
15     int shuiliang;
16     int shengyushuiliang;
17     
18     //方法一：接水
19     public void jieshui(int jieshuiliang){
20         
21         if(jieshuiliang > shuiliang){
22             System.out.println("已经没水了");
23         }
24         else
25         {
26             shengyushuiliang = shuiliang - jieshuiliang;
27             System.out.println("饮水机剩余水量 = " + shengyushuiliang);
28         }
29             
30     }
31     
32     //方法二：烧水
33     public void shaoshui(int time){
34         
35         int shuiwen = 20;
36         shuiwen = shuiwen + time * 10;
37         if(shuiwen > 100)
38         {
39             System.out.println("水已经开了");
40         }
41         else
42         {
43             System.out.println("现在水温 = " + shuiwen);
44         }
45         
46     }
47     
48 
49 }

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