1、设计四个类,分别是:(知识点:抽象类及抽象方法)

(1)Shape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。

(2)2个子类:

  1)Rectangle表示矩形类,增加两个属性,Width表示长度、height表示宽度,重写getPer、getArea和showAll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)。

  2)Circle表示圆类,增加1个属性,radius表示半径,重写getPer、getArea和showAll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。

package com.gyq.chapterOne;

public abstract class Shape1 {
    protected double area;
    protected double per;
    protected String color;
    
    public Shape1() {
        
    }
    
    public Shape1(String color) {
        super();
        this.color = color;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public abstract void getArea();
    public abstract void getPer();
    public abstract void showAll();
    
}

  

package com.gyq.chapterOne;

import java.awt.Color;

public class Rectangle1 extends Shape1{
    private int width;
    private int height;
    
    public Rectangle1() {

    }
    
    public Rectangle1(int width, int height,String color) {
        super(color);
        this.width = width;
        this.height = height;
    }

    @Override
    public void getArea() {
        area = width * height;
    }

    @Override
    public void getPer() {
        per = (width + height) * 2;    
    }

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

  

package com.gyq.chapterOne;

public class Circle1 extends Shape1{
    private int radius;
    
    public Circle1() {
        super();
        // TODO Auto-generated constructor stub
    }
    
    public Circle1(int radius,String color) {
        super(color);
        this.radius = radius;
    }

    @Override
    public void getArea() {
        area = radius * radius * 3.14;
    }

    @Override
    public void getPer() {
        per = 2 * radius * 3.14;
    }

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

  

package com.gyq.chapterOne;

public class PolyDeom {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Rectangle1 r = new Rectangle1(3, 4, "蓝");
        Circle1 c = new Circle1(2, "黄");
        r.getArea();
        r.getPer();
        r.showAll();
        c.getArea();
        c.getPer();
        c.showAll();
    }

}

  

2、Cola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,在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 com.gyq.chapterOne;

public class ColaEmployee {
    protected String name;
    protected int birthday;
    
    public ColaEmployee() {
        
    }

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

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

  

package com.gyq.chapterOne;

public class SalariedEmployee extends ColaEmployee{
    double Salary;

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

    public SalariedEmployee(double salary,String name, int birthday) {
        super(name, birthday);
        this.Salary = salary;
    }
    public double getSalary(int month) {
        if (super.birthday==birthday) {
            return Salary + 100;
        } else {
            return Salary;
        }
        
    }
    
}

  

package com.gyq.chapterOne;

public class HourlyEmployee extends ColaEmployee{
    int hourSalary;
    int hour;
    public HourlyEmployee() {
        super();
        // TODO Auto-generated constructor stub
    }
    
    public HourlyEmployee(int hourSalary, int hour,String name, int birthday) {
        super(name, birthday);
        this.hourSalary = hourSalary;
        this.hour = hour;
    }
    public double getSalary(int month) {
        if (super.birthday==birthday) {
            if (hour>160) {
                return hourSalary * 160 + hourSalary * (hour - 160) * 1.5 +100;
            } else {
                return hourSalary*hour+100;
            }
        } else {
            if (hour>160) {
                return hourSalary * 160 + hourSalary * (hour - 160) * 1.5;
            } else {
                return hourSalary*hour;
            }
        }
        
    }
}

  

package com.gyq.chapterOne;

public class SalesEmployee extends ColaEmployee{
    int monthSales;
    double add;
    public SalesEmployee() {
        super();
        // TODO Auto-generated constructor stub
    }
    
    public SalesEmployee(int monthSales, double add,String name, int birthday) {
        super(name, birthday);
        this.monthSales = monthSales;
        this.add = add;
    }
    public double getSalary(int mon) {
        if (super.birthday==birthday) {
            return monthSales*add+100;
        } else {
            return monthSales*add;
        }
    }
}

  

package com.gyq.chapterOne;

import java.time.Month;

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

  

package com.gyq.chapterOne;

public class TestCompany {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ColaEmployee[] a= {new SalariedEmployee(10000,"James",4),new HourlyEmployee(60, 200, "Licy", 10),new SalesEmployee(9000, 1.8, "Coco", 2)};
        for (int i = 0; i < a.length; i++) {
            new Company().getSalary(a[i], 4);
        }
    }

}

  

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。

  

package com.gyq.chapterOne;

public interface Fruit {
    
}

  

package com.gyq.chapterOne;

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

  

package com.gyq.chapterOne;

public class Banana implements Fruit{
    public Banana() {
        System.out.println("创建了一个香蕉对象");
    }
}

  

package com.gyq.chapterOne;

public class Grape implements Fruit{
    public Grape() {
        System.out.println("创建了一个葡萄对象");
    }
}

  

package com.gyq.chapterOne;

import java.util.Scanner;

public class Gardener {
    public Fruit create() {
        System.out.println("请输入你想要创建的水果对象");
        Scanner input = new Scanner(System.in);
        String name = input.next();
        Fruit fruit = null;
        switch (name) {
        case "苹果":
            fruit = new Apple();
            break;
        case "香蕉":
            fruit = new Banana(); 
            break;
        case "葡萄":
            fruit = new Grape();
            break;
        }
        input.close();
        
        return fruit;
    }
}

  

package com.gyq.chapterOne;

public class FruitDeom {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Gardener g = new Gardener();
        g.create();
    }

}