实验二 继承与接口实验

1、实验二 继承与接口一、实验目的1. 掌握类的继承机制。2. 熟悉类中成员变量和方法的访问控制。3. 掌握接口与包的使用，熟悉方法的多态性。二、实验内容1. 定义父类及子类，在子类中重写父类的方法2. 练习接口与包的使用三、.实验步骤与要求第1题 继承编写一个Java应用程序，除了主类外，该程序中还有4个类：People, ChinaPeople, AmericanPeople 和 BeijingPeople类。此四个类的继承关系如下图所示：要求ChinaPeople，American类均重写其父类People类的speakHello, averageHeight, averageWeight方

2、法，BeijingPeople类重写其父类ChinaPeople类的speakHello, averageHeight, averageWeight方法。People类 变量 方法protected double height public void speak Hello() protected double weight public void averageHeight() public void averageWeight()ChinaPeople类方法： public void chinaGongfu()AmericanPeople类方法：Public void americanBo

3、xing()BeijingPeople类方法：Public void beijingOpera()源代码：package people;class peopleprotected double height ; protected double weight ; public void speakHello() /问候语的函数System.out.println("hello");public void averageHeight()/人们的平均身高 height=170;System.out.println(+height);public void averageWeig

4、ht()/人们的平均体重 weight=120;System.out.println(+weight);class Chinapeople extends peoplepublic void speakHello() System.out.println("你好");public void averageHeight() height=172;System.out.println(+height);public void averageWeight() weight=115;System.out.println(+weight);public void chinaGongf

5、u()/中国功夫的方法System.out.println("中国功夫");class Americanpeople extends peoplepublic void speakHello() System.out.println("hello");public void averageHeight() height=180;System.out.println(+height);public void averageWeight() weight=150;System.out.println(+weight);public void american

6、Boxing()/美国拳击的方法System.out.println("americanBoxing");class Beijingpeople extends Chinapeoplepublic void speakHello() System.out.println("北京欢迎你");public void averageHeight() height=168;System.out.println(+height);public void averageWeight() weight=125;System.out.println(+weight);c

7、lass Examplepublic static void main(String args)people p =new people();Chinapeople c=new Chinapeople();Americanpeople a=new Americanpeople();Beijingpeople b=new Beijingpeople();p.averageHeight();p.averageWeight();p.speakHello();c.averageHeight();c.averageWeight();c.chinaGongfu();c.speakHello();a.ave

8、rageHeight();a.averageWeight();a.americanBoxing();a.speakHello();b.averageHeight();b.averageWeight();b.speakHello();结果截图：第2题 上转型对象要求有一个abstract类，类名为Employee。Employee的子类有YearWorker,MonthWorker和WeekWorker。YearWorker按年领取薪水，MonthWorker按月领取薪水，WeekWorker按周领取薪水。Employee类有一个abstract方法：public abstract earnin

9、gs();子类必须重写父类的earnings()方法，给出各自领取报酬的具体方式。有一个Company类，该类用employee数组作为成员，employee数组的单元可以是YearWorker对象的上转型对象、MonthWorker对象的上转型对象或WeekWorker对象的上转型对象。程序能输出Company对象一年需要支付的薪水总额。源代码：package people; abstract class Employee int salary;public abstract void earnings();class YearWorker extends Employee public v

10、oid earnings() salary=200;System.out.println("年薪：" +salary*365);class MonthWorker extends Employee public void earnings() salary=100;System.out.println("月薪："+salary*30+" 一年薪水： "+salary*30*12);class WeekWorker extends Employee public void earnings() salary=80;System.out.

11、println("周薪："+salary*7+" 一年薪水： "+salary*365);public class Company public static void main(String args) Employee e=new Employee3; e0=new YearWorker(); e0.earnings(); e1=new MonthWorker(); e1.earnings(); e2=new WeekWorker(); e2.earnings(); 结果截图：第3题 接口回调要求有一个ComputeTotalSales接口，该接口中

12、有一个方法：public double totalSalesByYear()，有三个实现该接口的类：Television,Computer和Mobile。这三个类通过实现接口computeTotalSales，给出自己的年销售额。有一个Shop类，该类用computeTotalSales数组作为成员，computeTotalSales数组的单元可以存放Television对象的引用、Computer对象的引用或Mobile对象的引用。程序能输出Shop对象的年销售额。源代码：package people;interface ComputeTotalSalespublic double tota

13、lSalesByYear();class Television implements ComputeTotalSalespublic double totalSalesByYear()double sale=100;return sale*365;class computer implements ComputeTotalSalespublic double totalSalesByYear()double sale=200;return sale*365;class Mobile implements ComputeTotalSalespublic double totalSalesByYe

14、ar()double sale=220;return sale*365;public class shop public static void main(String args) ComputeTotalSales c; c=new ComputeTotalSales3; c0=new Television(); System.out.println("电视机的年销售量："+c0.totalSalesByYear(); c1=new computer(); System.out.println("电脑的年销售量："+c1.totalSalesByYear(); c2=ne