1、设计个类,分别是:(知识点:抽象类及抽象方法)

1Shape表示图形类,有面积属性area、周长属性per,颜色属性color,有两个构造方法(一个是默认的、一个是为颜色赋值的),还有3个抽象方法,分别是:getArea计算面积、getPer计算周长、showAll输出所有信息,还有一个求颜色的方法getColor

22个子类:

1Rectangle表示矩形类,增加两个属性,Width表示长度、height表示宽度,重写getPergetAreashowAll三个方法,另外又增加一个构造方法(一个是默认的、一个是为高度、宽度、颜色赋值的)。

2Circle表示圆类,增加1个属性,radius表示半径,重写getPergetAreashowAll三个方法,另外又增加两个构造方法(为半径、颜色赋值的)。

 3)一个测试类PolyDemo,在main方法中,声明创建每个子类的对象,并调用2个子类的showAll方法。

 

public abstract class Shape {
	protected double area;
	protected double per;
	protected String color;

	public Shape() {

	}

	public Shape(String color) {
		this.color = color;
	}

	public abstract void s();

	public abstract void c();

	public abstract void showAll();
}

 

  

public class Rectangle extends Shape {
	double width;
	double height;

	public Rectangle() {

	}

	public Rectangle(double width, double height, String color) {
		super();
		this.width = width;
		this.height = height;
		this.color = color;
	}

	public void s() {
		area = width * height;

	}


	public void c() {
		per = (width + height) * 2;
	}


	public void showAll() {
		System.out.println("矩形面积为:" + area + ",周长为:" + per+",颜色:"+color);
	}

}

  

public class Circle extends Shape {
	double radius;

	public Circle() {

	}

	public Circle(double radius, String color) {
		this.color = color;
		this.radius = radius;
	}

	public void s() {

		area = radius * radius * 3.14;
	}


	public void c() {
	
		per = 2 * radius * 3.14;
	}


	public void showAll() {
	
		System.out.println("圆的面积为:" + area + ",周长为:" + per+",颜色:"+color);
	}

}

  

package demoa12_1twelfthweek_Thursday;

public class Test1 {
	public static void main(String[] args) {
		Circle circle = new Circle(4,"black");
		Rectangle rectangle = new Rectangle(4,7,"green");
		circle.s();
		circle.c();
		circle.showAll();
		
		rectangle.s();
		rectangle.c();
		rectangle.showAll();
		
	}

}

  

2Cola公司的雇员分为以下若干类:(知识点:多态)

(1) ColaEmployee :这是所有员工总的父类,属性:员工的姓名,员工的生日月份。

Ÿ 方法:getSalary(int month) 根据参数月份来确定工资,如果该月员工过生日,则公司会额外奖励100 元。

(2) SalariedEmployee ColaEmployee 的子类,拿固定工资的员工。

Ÿ 属性:月薪

(3) HourlyEmployee ColaEmployee 的子类,按小时拿工资的员工,每月工作超出160 小时的部分按照1.5 倍工资发放。

Ÿ 属性:每小时的工资、每月工作的小时数

(4) SalesEmployee ColaEmployee 的子类,销售人员,工资由月销售额和提成率决定。

Ÿ 属性:月销售额、提成率

(5) 定义一个类Company,在该类中写一个方法,调用该方法可以打印出某月某个员工的工资数额,写一个测试类TestCompany,main方法,把若干各种类型的员工放在一个ColaEmployee 数组里,并单元出数组中每个员工当月的工资。

 

package pra;

public class ColaEmployee {
    String name;
    int month;

    public ColaEmployee() {

    }

    public ColaEmployee(String name, int month) {
        super();
        this.name = name;
        this.month = month;
    }

    public double getSalary(int month) {
        return 0;
    }

}

 

  

package pra;

public class SalariedEmployee extends ColaEmployee {
    double monSalary;

    public SalariedEmployee() {
        super();
        // TODO Auto-generated constructor stub
    }

    public SalariedEmployee(String name, int month, double monSalary) {
        super(name, month);
        this.monSalary = monSalary;
    }

    public double getSalary(int month) {
        if (super.month == month) {
            return monSalary + 100;
        } else {
            return monSalary;
        }
    }

}

  

package pra;

public class HourlyEmployee extends ColaEmployee {
    private int hourSalary;
    private int hourNum;

    public HourlyEmployee(String name, int month, int hourSalary, int hourNum) {
        super(name, month);
        this.hourSalary = hourSalary;
        this.hourNum = hourNum;

    }

    public double getSalary(int month) {
        if (super.month == month) {
            if (hourNum > 160) {
                return hourSalary * 160 + hourSalary * (hourNum - 160) * 1.5 + 100;
            } else {
                return hourSalary * hourNum + 100;
            }
        } else {
            if (hourNum > 160) {
                return hourSalary * 160 + hourSalary * (hourNum - 160) * 1.5;
            } else {
                return hourSalary * hourNum;
            }
        }

    }

}

  

package pra;

public class SalesEmployee extends ColaEmployee {
    private int monthSales;
    private double royaltyRate;

    public SalesEmployee(String name, int month, int monthSales, double royaltyRate) {
        super(name, month);
        this.monthSales = monthSales;
        this.royaltyRate = royaltyRate;
    }

    public double getSalary(int month) {
        if (super.month == month) {
            return monthSales * royaltyRate + 100;
        } else {
            return monthSales * royaltyRate;
        }
    }

}

  

package pra;

public class Company {
    public void getSalary(ColaEmployee c, int month) {
        System.out.println(c.name + "在" + month + "月的月薪为" + c.getSalary(month) + "元");
    }

}

  

package pra;

public class Text {
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        // 创建、初始化数组
        ColaEmployee[] cel = { new SalariedEmployee("salariedEmployee", 6, 25000), // name,month,月薪
                new HourlyEmployee("hourlyEmployee", 5, 200, 200), // name,month,时薪,小时数
                new SalesEmployee("salesEmployee", 3, 60000, 0.3)// name,month,月销售额,提成率
        };
        // 数组遍历
        for (int i = 0; i < cel.length; i++) {
            new Company().getSalary(cel[i], 7);
        }
    }

}

  

3利用接口实现动态的创建对象:(知识点:接口

1)创建4个类

1苹果

2香蕉

3葡萄

4园丁

2)在三种水果的构造方法中打印一句话.

以苹果类为例

class apple

{

public apple()

{

System.out.println(“创建了一个苹果类的对象”);

}

}

3)类图如下:

 

4)要求从控制台输入一个字符串,根据字符串的值来判断创建三种水果中哪个类的对象。

运行结果如图:

 

package demoa12_1twelfthweek_Thursday;

import java.util.Scanner;

interface Fruit{
	
}

class Apple implements Fruit {
	public Apple() {
		System.out.println("创建了一个苹果对象");
	}
}

class Pear implements Fruit {
	public Pear() {
		System.out.println("创建了一个梨对象");
	}
}

class Orange implements Fruit {
	public Orange() {
		System.out.println("创建了一个桔子对象");
	}
}
class Gardener{
	public Fruit create() {
		Scanner input = new Scanner(System.in);
		String name = input.next();
		
		Fruit fruit = null;
		switch(name){
		case "苹果":
			fruit = new Apple();
			break;
		case "梨":
			fruit = new Pear();
			break;
		case "桔子":
			fruit = new Orange();
			break;
		}
		
		input.close();
		
		return fruit;
	}
}

  

package demoa12_1twelfthweek_Thursday;

public class test2 {

	public static void main(String[] args) {
		Gardener g = new Gardener();
		g.create();

	}
}