三种方法实现灯亮

台灯开启不同颜色的灯亮

1、抽象类

package LESSON5;
//用抽象类  台灯类
class Lamp{
    private Buble buble;//类型为Buble的buble变量
    public Buble getBuble() {
        return buble;
    }
    public void setBuble(Buble buble) {
        this.buble = buble;
    }
    public void on(){
        buble.shine();        
    };
}
abstract class Buble {    
    public abstract void shine();
}
class RedBuble extends Buble{
    @Override
    public void shine() {
        System.out.println("red");        
    }    
}
class GreenBuble extends Buble{
    @Override
    public void shine() {
        System.out.println("green");        
    }    
}
public class Exercise4 {
    public static void main(String[] args) {
        RedBuble re=new RedBuble();
        GreenBuble gr=new GreenBuble();
        Lamp la=new Lamp();
        la.setBuble(re);//红灯
        la.on();//输出red      
    }
}

2、接口无get,set方法

package LESSON7;
class Lamp{
    private Buble buble;//类型为Buble的buble变量    
    public void on(Buble buble){
        buble.shine();        
    };
}
interface Buble {
    //抽象方法
    public void shine();
}
class RedBuble implements Buble{
    @Override
    public void shine() {
        System.out.println("red");        
    }    
}
class GreenBuble implements Buble{
    @Override
    public void shine() {
        System.out.println("green");        
    }    
}
public class Exercise3 {
    public static void main(String[] args) {
        RedBuble re =new RedBuble ();
        GreenBuble gr=new GreenBuble();
        Lamp la=new Lamp();
        la.on(re);
    }
}

3、接口有get,set方法

package LESSON6;
class Lamp{
    private Buble buble;//类型为Buble的buble变量
    //或者不用设置属性和get，set方法直接将Buble buble当函数参数传给on(),调用时直接传入
    public Buble getBuble() {
        return buble;
    }
    public void setBuble(Buble buble) {
        this.buble = buble;
    }
    public void on(){//(法2)public void on(Buble buble)
        buble.shine();        
    };
}
interface Buble {    
    public void shine();
}
class RedBuble implements Buble{
    @Override
    public void shine() {
        System.out.println("red");        
    }        
}
class GreenBuble implements Buble{
    @Override
    public void shine() {
        System.out.println("green");        
    }    
}
public class Exercise1 {   
    public static void main(String[] args) {
        RedBuble rb=new RedBuble();
        GreenBuble gb=new GreenBuble();        
        Lamp la=new Lamp();
//        la.on(rb);（法2）传入
        la.setBuble(rb);
        la.on();                
    }
}