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 school4; public class Shape { int area; int per; String color; public int getArea(int a,int b) { return area=a*b; } public int getPer(int a,int b) { return per=(a+b)*2; } public String getColor(String c) { return color=c; } public void showAll() { System.out.println("图形的面积是:"+area+"周长是:"+per+"颜色是:"+color); } } package school4; public class Rectangle extends Shape{ int Width; int Height; public int getPer(int Width,int Height) { return per=(Height+Width)*2; } public int getArea(int Width,int Height) { return area=Height*Width; } public String getColor(String c) { return color=c; } public void getShowall() { System.out.println("长是:"+Height+"宽是:"+Width+"图形的面积是:"+area+"周长是:"+per+"颜色是:"+color); } } package school4; public class Circle extends Shape{ int radius; public int getPer(int radius) { return per=3*2*radius; } public int getArea(int radius) { return area=3*radius*radius; } public String getColor(String c) { return color=c; } public void getShowall() { System.out.println("半径是:"+radius+"图形的面积是:"+area+"周长是:"+per+"颜色是:"+color); } } package school4; public class PolyDemo { public static void main(String[] args) { // TODO Auto-generated method stub Shape s=new Shape(); s.getArea(5, 7); s.getPer(5, 7); s.getColor("blue"); s.showAll(); Rectangle r=new Rectangle(); r.Width=10; r.Height=8; r.getArea(10, 8); r.getPer(10, 8); r.getColor("red"); r.getShowall(); Circle c=new Circle(); c.radius=5; c.getArea(5); c.getColor("yellow"); c.getPer(5); c.getShowall(); } }
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 school4; public class ColaEmployee { String name; int bmonth; public void getSalary(int month) { System.out.println("月份:"+month); } } package school4; public class SalariedEmployee extends ColaEmployee{ int mmoney; public void getsal(String name,int month,int bmonth, int mmoney) { if(month==bmonth) { System.out.println(name+"工资是:"+(mmoney+100)); }else { System.out.println(name+"工资是:"+mmoney); } } } package school4; public class HourlyEmployee extends ColaEmployee{ public void hsal(String name ,int hoursal,int mhour,int bmonth, int month){ if(month==bmonth) { if(mhour<=160 && mhour>0) { System.out.println(name+"工资是"+(hoursal*mhour)+100); }else { System.out.println(name+"工资是"+(((mhour-160)*hoursal+(hoursal*160))+100)); } }else { if(mhour<=160 && mhour>0) { System.out.println(name+"工资是"+(hoursal*mhour)); }else { System.out.println(name+"工资是"+(((mhour-160)*hoursal+(hoursal*160)))); } } } } package school4; public class SalesEmployee extends ColaEmployee { int monthxiaoshou; int tichenglv; public void xiaoshouSalar(String name,int mxiaoshou,int tichenglv,int bmonth,int month) { if(month==bmonth) { System.out.println(name+"工资是"+(mxiaoshou*(1+tichenglv)+100)); }else { System.out.println(name+"工资是"+(mxiaoshou*(1+tichenglv))); } } } package school4; public class Company { public void method(ColaEmployee a) { if(a instanceof HourlyEmployee) { HourlyEmployee H =(HourlyEmployee)a; H.hsal("张三",45,175,6,6); }else if(a instanceof SalariedEmployee) { SalariedEmployee c=(SalariedEmployee)a; c.getsal("李四",7,7,1000); }else if(a instanceof SalesEmployee) { SalesEmployee b = (SalesEmployee)a; b.xiaoshouSalar("王五",2000,3,5,6); } } }
package school4; public class ColaEmployee { String name; int bmonth; public void getSalary(int month) { System.out.println("月份:"+month); } } package school4; public class SalariedEmployee extends ColaEmployee{ int mmoney; public void getsal(String name,int month,int bmonth, int mmoney) { if(month==bmonth) { System.out.println(name+"工资是:"+(mmoney+100)); }else { System.out.println(name+"工资是:"+mmoney); } } } package school4; public class HourlyEmployee extends ColaEmployee{ public void hsal(String name ,int hoursal,int mhour,int bmonth, int month){ if(month==bmonth) { if(mhour<=160 && mhour>0) { System.out.println(name+"工资是"+(hoursal*mhour)+100); }else { System.out.println(name+"工资是"+(((mhour-160)*hoursal+(hoursal*160))+100)); } }else { if(mhour<=160 && mhour>0) { System.out.println(name+"工资是"+(hoursal*mhour)); }else { System.out.println(name+"工资是"+(((mhour-160)*hoursal+(hoursal*160)))); } } } } package school4; public class SalesEmployee extends ColaEmployee { int monthxiaoshou; int tichenglv; public void xiaoshouSalar(String name,int mxiaoshou,int tichenglv,int bmonth,int month) { if(month==bmonth) { System.out.println(name+"工资是"+(mxiaoshou*(1+tichenglv)+100)); }else { System.out.println(name+"工资是"+(mxiaoshou*(1+tichenglv))); } } } package school4; public class Company { public void method(ColaEmployee a) { if(a instanceof HourlyEmployee) { HourlyEmployee H =(HourlyEmployee)a; H.hsal("张三",45,175,6,6); }else if(a instanceof SalariedEmployee) { SalariedEmployee c=(SalariedEmployee)a; c.getsal("李四",7,7,1000); }else if(a instanceof SalesEmployee) { SalesEmployee b = (SalesEmployee)a; b.xiaoshouSalar("王五",2000,3,5,6); } } }
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:
package school4; public class Apple implements Fruit { public Apple() { System.out.println("创建了一个苹果对象"); } } package school4; public class Banana implements Fruit{ public Banana() { System.out.println("创建一个香蕉类的对象"); } } package school4; public class Grape implements Fruit{ public Grape() { System.out.println("创建一个葡萄类的对象"); } } package school4; import java.util.Scanner; public interface Fruit { public static void main(String[] args) { // TODO Auto-generated method stub @SuppressWarnings("resource") Scanner s=new Scanner(System.in); System.out.println("请输入水果名字:"); String a=s.next(); if(a.equals("苹果")) { new Apple(); }else if(a.equals("香蕉")){ new Banana(); }else if(a.equals("葡萄")){ new Grape(); }else { System.out.println("无此类水果"); } } }
(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: