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。 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。 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。 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。 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。 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。 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 itheima01.com; public abstract class Shape { double area; double per; String color; public Shape(){ } public Shape(String color){ this.color = color; } public abstract double getArea(); public abstract double getPer(); public abstract void showAll(); public String getColor(){ return this.color; } } package itheima01.com; public class Rectangle extends Shape{ int weidth; int height; public Rectangle() { } public Rectangle(int weidth,int height,String color){ super(color); this.weidth = weidth; this.height = height; } public double getArea() { this.area = weidth * height; return this.area; } public double getPer() { this.per = 2 * (weidth + height); return this.per; } public void showAll() { System.out.println("该矩形长为"+this.weidth+",宽为"+this.height+",周长为"+this.getPer()+",面积为"+this.getArea()+",颜色为"+this.getColor()); } } package itheima01.com; public class Circle extends Shape { double radius; double pi = Math.PI; public Circle(){ } public Circle(double radius,String color){ super(color); this.radius = radius; } public double getArea() { double area =pi * radius *radius; return area; } public double getPer() { double per = 2 * pi * radius; return per; } public void showAll() { System.out.println("半径为"+this.radius+"的圆,周长为"+this.getPer()+",面积为"+this.getArea()+",颜色为"+this.getColor()); } } package itheima01.com; public class PolyDemo { public static void main(String[] args) { Rectangle r = new Rectangle(8,9,"brown"); Circle c = new Circle(10,"pink"); r.showAll(); c.showAll(); } } 2.package itheima01.com; public class ColaEmployee { String name; int month; public ColaEmployee() { } public ColaEmployee(String name, int month) { this.name = name; this.month = month; } public double getSalary(int month) { return 0; } }package itheima01.com; public class SalariedEmployee extends ColaEmployee { double monSalary; 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 itheima01.com; 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 itheima01.com; 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 itheima01.com; public class TestCompany { public static void main(String[] args) { ColaEmployee[] z = { new SalariedEmployee("员工: 王二麻子", 5, 12300), new HourlyEmployee("员工: 张三", 9, 140, 360), new SalesEmployee("员工 :李四", 7, 873200, 0.25) }; for (int i = 0; i <z.length; i++) { new Company().getSalary(z[i],8); } } }package itheima01.com; public class Company { public void getSalary(ColaEmployee k,int month) { System.out.println(k.name + "在" + month + "月的月薪为" + k.getSalary(month)+"元"); } } 3.package itheima01.com; public interface Fruit { void apple(); void banana(); void orange(); } package itheima01.com; public class apple implements Fruit{ public void apple(){ System.out.println("创建了一个苹果类的对象"); } @Override public void banana(){ } @Override public void orange(){ } } package itheima01.com; public class banana implements Fruit { public void banana(){ System.out.println("创建了一个香蕉类的对象"); } @Override public apple(){ } @Override public orange(){ } } package itheima01.com; import java.util.*; public class Text { public static void main(String[]args){ Fruit b=new banana(); Scanner input=new Scanner (System.in); System.out.println("请输入您要创建的类:"); String attr=input.nextLine(); if (attr.equals("banana")){ Fruit fruit =new banana(); fruit.banana(); } else if (attr.equals("orange")){ Fruit fruit =new orange(); fruit.orange(); } else if (attr.equals("apple")){ Fruit fruit =new apple(); fruit.apple(); } else System.out.println("输入有误"); } } package itheima01.com; public class orange implements Fruit { public void orange(){ System.out.println("创建了一个橙子的对象"); } @Override public void apple(){ } @Override public void banana(){ } }