1.編寫程序實現樂手彈奏樂器。樂手可以彈奏不同的樂器從而發出不同的聲音。可以彈奏的樂器包括二胡、鋼琴和小提琴。

/**
?*?樂器類
?*?@author?Administrator
?*
?*/
public?class?Instrument?{
	public?void?makeSound(){
		System.out.println("發出聲音");
	}
}
/**
?*?鋼琴類
?*?@author?Administrator
?*
?*/
public?class?Piano?extends?Instrument{
	public?void?makeSound(){
		System.out.println("鋼琴聲...命運交響曲...");
	}
}
/**
?*?小提琴類
?*?@author?Administrator
?*
?*/
public?class?Violin?extends?Instrument{
	public?void?makeSound(){
		System.out.println("小提琴聲音..梁祝...");
	}
}
/**
?*?二胡類
?*?@author?Administrator
?*
?*/
public?class?Erhu?extends?Instrument{
	public?void?makeSound(){
		System.out.println("二胡聲音...二泉映月..");
	}
}
/**
??*?樂手類
??*?@author?Administrator
??*
??*/
public?class?Musician?{
	public?static?void?play(Instrument?instrument){
		instrument.makeSound();
	}	
	public?static?void?main(String[]?args)?{
		Instrument?i1?=?new?Piano();
		play(i1);		
		Instrument?i2?=?new?Violin();
		play(i2);		
		Instrument?i3?=?new?Erhu();
		play(i3);
	}
}

2.編寫程序實現比薩制作。需求說明編寫程序，接收用戶輸入的信息，選擇需要制作的比薩。可供選擇的比薩有：培根比薩和海鮮比薩

/**
?*?定義抽象類
*/
public?abstract?class?Pizza?{
	private?String?name;
	private?int?price;
	private?int?size;
	
	public?Pizza()?{
		super();
	}
	public?Pizza(String?name,?int?price,?int?size)?{
		super();
		this.name?=?name;
		this.price?=?price;
		this.size?=?size;
	}
	public?String?getName()?{
		return?name;
	}
	public?void?setName(String?name)?{
		this.name?=?name;
	}
	public?int?getPrice()?{
		return?price;
	}
	public?void?setPrice(int?price)?{
		this.price?=?price;
	}
	public?int?getSize()?{
		return?size;
	}
	public?void?setSize(int?size)?{
		this.size?=?size;
	}
	public?abstract?void??show();
		?	?
}
/**
?*?培根比薩
*/
public?class?BaconPizza?extends?Pizza{
	private?int?gram;//克數		
	public?BaconPizza()?{
		super();
	}
	public?BaconPizza(String?name,?int?price,?int?size,?int?gram)?{
		super(name,?price,?size);
		this.gram?=?gram;
	}
	public?int?getGram()?{
		return?gram;
	}
	public?void?setGram(int?gram)?{
		this.gram?=?gram;
	}
	public?void?show()?{
		System.out.println("名稱："+super.getName());
		System.out.println("價格："+super.getPrice()+"元");
		System.out.println("大小："+super.getSize()+"寸");
		System.out.println("培根克數："+this.gram);		
	}
}
/**
?*?海鮮比薩
*/
public?class?SeaFoodPizza?extends?Pizza{
	private?String?mixture;//配料	
	public?SeaFoodPizza()?{
		super();
	}
	public?SeaFoodPizza(String?name,?int?price,?int?size,?String?mixture)?{
		super(name,?price,?size);
		this.mixture?=?mixture;
	}
	public?String?getMixture()?{
		return?mixture;
	}
	public?void?setMixture(String?mixture)?{
		this.mixture?=?mixture;
	}
	@Override
	public?void?show()?{		
		System.out.println("名稱："+super.getName());
		System.out.println("價格："+super.getPrice()+"元");
		System.out.println("大小："+super.getSize()+"寸");
		System.out.println("配料："+this.mixture);	
	}
}
/**
?*?比薩制作
*/
public?class?PizzaFactory?{
	public?static?Pizza?makePizza(){
		System.out.println("請選擇想要制作的比薩(1.培根比薩?2.海鮮比薩)：");
		Scanner?scanner?=?new?Scanner(System.in);
		int?i?=?scanner.nextInt();
		Pizza?pizza?=?null;		
		if(i==1){
			//制作培根比薩
			System.out.println("請輸入培根克數：");
			int?gram?=?scanner.nextInt()?;			
			System.out.println("請輸比薩大小：");
			int?size?=??scanner.nextInt();			
			System.out.println("請輸入比薩價格：");
			int?price?=??scanner.nextInt();					
			pizza?=?new?BaconPizza("培根比薩",?price,?size,?gram);			
		}else?if(i==2){
			//制作海鮮比薩
			System.out.println("請輸入配料信息：");
			String?mixture??=??scanner.next();
			
			

????System.out.println("請輸比薩大小：");
????			int?size?=??scanner.nextInt();
????			
????			

????System.out.println("請輸入比薩價格：");
????????			int?price?=??scanner.nextInt();
????????			pizza?=?new?SeaFoodPizza("海鮮比薩",?price,?size,?mixture);
????????		}
????????		return?pizza;
	}	
	public?static?void?main(String[]?args)?{
		Pizza?pizza?=?makePizza();
		pizza.show();
	}
}

3.編寫程序實現軟料購買：編寫程序，接收用戶輸入的信息，選擇購買的飲料。可供選擇的飲料有：咖啡、礦泉水和可樂。其中，購買咖啡時可以選擇：加糖、加奶還是什么都不加。購買可樂時可以選擇：買可口可樂還是百事可樂。

//飲料類
public?class?Drink?{
	private?String?name;
	private?int?volume;
	public?Drink()?{
		super();
	}
	public?Drink(String?name,?int?volume)?{
		super();
		this.name?=?name;
		this.volume?=?volume;
	}
	public?String?getName()?{
		return?name;
	}
	public?void?setName(String?name)?{
		this.name?=?name;
	}
	public?int?getVolume()?{
		return?volume;
	}
	public?void?setVolume(int?volume)?{
		this.volume?=?volume;
	}	
	public?void?show(){
		System.out.println("您購買的飲料信息如下：");
		System.out.println("名稱："+name);
		System.out.println("容量："+volume);		
	}	
}
//咖啡類
public?class?Coffee?extends?Drink{
	private?String?mixture;//添加物
	public?Coffee()?{
		super();
	}
	public?Coffee(String?name,int?volume,?String?mixture)?{
		super(name,volume);
		this.mixture?=?mixture;
	}	
	public?String?getMixture()?{
		return?mixture;
	}
	public?void?setMixture(String?mixture)?{
		this.mixture?=?mixture;
	}
	public?void?show(){
		System.out.println("您購買的飲料信息如下：");
		System.out.println("名稱："+super.getName());
		System.out.println("添加配料："+this.getMixture());
		System.out.println("容量："+super.getVolume());		
	}	
}
?//飲料工廠類
public?class?DrinkFactory?{
	public??static?Drink?getDrink(String?no){
		Scanner?input?=?new?Scanner(System.in);
		Drink?drink?=?null;
		if("1".equals(no)){
			System.out.println("請輸入購買容量：");
			int?volume?=?input.nextInt();
			System.out.println("請問是否要配料（1、加糖?2、加奶?3、什么也不加）");
			int?choice?=?input.nextInt();
			String?mixture;
			switch(choice){
			case?1:?mixture?="加糖";break;
			case?2:?mixture?="加奶";break;
			default?:?mixture="什么一個不加";
			}
			drink?=?new?Coffee("咖啡",volume,?mixture);
		}else?if("2".equals(no)){
			//省略			
		}else?if("3".equals(no)){
			//省略		}
		return?drink;
	}
}
//測試類
public?class?TestDrink?{
	public?static?void?main(String[]?args)?{
		Scanner?input?=?new?Scanner(System.in);
		System.out.println("請選擇飲料（1.咖啡??2?礦泉水??3?可樂）：");
		String?choice?=?input.next();
		Drink?drink?=?DrinkFactory.getDrink(choice);
		drink.show();		
	}
}

以上就是動力節點java培訓機構的小編針對“編程基礎分享，Java多態的練習題”的內容進行的回答，希望對大家有所幫助，如有疑問，請在線咨詢，有專業老師隨時為你服務。