java类的练习–下面给出一个根据雇员类型利用多态性完成…

题目

下面给出一个根据雇员类型利用多态性完成工资单计算的程序。定义一个类Employee作为超类，Employee的子类有Boss（每星期发给他固定工资，而不计工作时间）、PieceWorker（按其生产的产品数发放工资）、HourlyWorker（根据工作时间长短发放工资）。对所有雇员类型都使用earnings()方法完成其工资单的计算，但每个人挣的工资按他所属的雇员类计算，所有雇员类都是从超类Employee派出生的。所以在超类中声明earnings()方法，该方法没有实质性工作，而是在每个子类都提供恰当的earnings()方法的重写。为了计算雇员的工资，程序仅使用雇员对象的一个超类引导并调用earnings()方法。

参考代码

// 参考文件名 Ch3.java


//Employee超类的定义
class Employee {
	private String name;

	public Employee(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

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

	public String toString() {
		return name;
	}

	public double earnings() {
		return 0.0;
	}
}

//定义Boss类，为Employee的子类
class Boss extends Employee {
	private Double weeklySalary;

	public Boss(String name, double s) { // 定义Boss类的构造方法
		super(name);
		setWeeklySalary(s);
	}

	public void setWeeklySalary(Double weeklySalary) {
		this.weeklySalary = weeklySalary;
	}

	public double earnings() { // 重写父类的 earnings()方法
		return weeklySalary;
	}

	public String toString() {
		return "Boss: " + super.toString();
	}
}

//定义PieceWorker类，为Employee的子类
class PieceWorker extends Employee {
	private Double salary;
	private Integer piece;

	public PieceWorker(String name, Integer p, Double s) {
		super(name);
		setSalary(s);
		setPiece(p);
	}

	public void setPiece(Integer p) {
		this.piece = p;
	}

	public void setSalary(Double s) {
		this.salary = s;
	}

	public double earnings() {
		return piece * salary;
	}

	public String toString() {
		return "PieceWorker: " + super.toString();
	}
}

//定义HourlyWorker类，为Employee的子类
class HourlyWorker extends Employee {
	private Double salary;
	private Integer hour;

	public HourlyWorker(String name, Integer h, Double s) {
		super(name);
		setSalary(s);
		setHour(h);
	}

	public void setHour(Integer h) {
		this.hour = h;
	}

	public void setSalary(Double s) {
		this.salary = s;
	}

	public double earnings() {
		return this.hour * salary;
	}

	public String toString() {
		return "HourlyWorker: " + super.toString();
	}
}

public class Ch3 {
	public static void main(String args[]) {
		Employee ref; // 定义一个父类声明ref
		ref = new Boss("魏无羡", 3000); // 父类引用指向子类对象
		System.out.println(ref + ", weeklySalary:" + ref.earnings());
		ref = new PieceWorker("王也", 3, 400.0);
		System.out.println(ref + ", weeklySalary:" + ref.earnings());
		ref = new HourlyWorker("张小凡", 13, 34.0);
		System.out.println(ref + ", weeklySalary:" + ref.earnings());
	}
}