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ChinaPeopl，eAmerican类均重写其父类People类的speakHello,averageHeight,averageWe方法ht，BeijingPeop类重

2、写其父类ChinaPeopl类的speakHello,averageHeight,averageWe法。htPeople类变量方法protecteddoubleheightpublicvoidspeakHello()protecteddoubleweightpublicvoidaverageHeight。publicvoidaverageWeight()ChinaPeople类方法：publicvoidchinaGongfu()AmericanPeople类方法：PublicvoidamericanBoxing()BeijingPeople类方法：PublicvoidbeijingOpera(

3、)源代码：packagepeople;classpeopleprotecteddoubleheight;protecteddoubleweight;publicvoidspeakHello()/问候语的函数System.out.println(hello);publicvoidaverageHeight()/人们的平均身高height=170;System.out.println(+height);publicvoidaverageWeight()/人们的平均体重weight=120;System.out.println(+weight);classChinapeopleextendspeop

4、lepublicvoidspeakHello()System.out.println(你好)；publicvoidaverageHeight()height=172;System.out.println(+height);publicvoidaverageWeight()weight=115;System.out.println(+weight);publicvoidchinaGongfu()/中国功夫的方法System.out.println(中国功夫)；classAmericanpeopleextendspeoplepublicvoidspeakHello()System.out.prin

5、tln(hello);publicvoidaverageHeight()height=180;System.out.println(+height);publicvoidaverageWeight()weight=150;System.out.println(+weight);publicvoidamericanBoxing()/美国拳击的方法System.out.println(americanBoxing);classBeijingpeopleextendsChinapeoplepublicvoidspeakHello()System.out.println(北京欢迎你)；publicvo

6、idaverageHeight()height=168;System.out.println(+height);publicvoidaverageWeight()weight=125;System.out.println(+weight);classExamplepublicstaticvoidmain(Stringargs)peoplep=newpeople();Chinapeoplec=newChinapeople();Americanpeoplea=newAmericanpeople();Beijingpeopleb=newBeijingpeople();p.averageHeight(

7、);p.averageWeight();p.speakHello();c.averageHeight();c.averageWeight();c.chinaGongfu();c.speakHello();a.averageHeight();a.averageWeight();a.americanBoxing();a.speakHello();b.averageHeight();b.averageWeight();b.speakHello();结果截图：奥ProblemsJavaidoc层DechratiotnExample(3)JavaApplication170.012,0hello172.

8、0115.6中国正夫：180.0150.0americanBoxinghello168.0125.0北京一双阻弟第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：publicabstractearnings();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

9、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WeekWorke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：packagepeople;abstractclassEmployeeintsalary;publicabstractvoidearnings();classYearWorkerextendsEmployeepublicvoidearnings()salary=200;System.out.println(年薪：+salary*365);classMonthWorkerextendsE

10、mployeepublicvoidearnings()salary=100;System.out.println(月薪：+salary*30+一年薪水：+salary*30*12);classWeekWorkerextendsEmployeepublicvoidearnings()salary=80;System.out.println(周薪：+salary*7+一年薪水：+salary*365);publicclassCompanypublicstaticvoidmain(Stringargs)Employeee=newEmployee3;e0=newYearWorker();e0.earn

11、ings();e1=newMonthWorker();e1.earnings();e2=newWeekWorker();e2.earnings();结果截图：盟ProblemsJavadoc圜CompanyJava.年译:73&00AM：39&0一年承水；36&00,flF=56&一年隼水;2920第3题接口回调要求有一个ComputeTotalSales接口，该接口中有一个方法：publicdouble321521058丫丫。21(),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

12、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：packagepeople;interfaceComputeTotalSalespublicdoubletotalSalesByYear();classTelevisionimplementsComputeTotalSalespublicdoubletotalSalesByYear()doublesale=100;returnsale*365;class

13、computerimplementsComputeTotalSalespublicdoubletotalSalesByYear()doublesale=200;returnsale*365;classMobileimplementsComputeTotalSalespublicdoubletotalSalesByYear()doublesale=220;returnsale*365;publicclassshoppublicstaticvoidmain(Stringargs)ComputeTotalSalesc;c=newComputeTotalSales3;c0=newTelevision();System.out.println(电视机的年销售量：+c0.totalSalesByYear();c1=newcomputer();System.out.println(电脑的年销售量：+c1.totalSalesByYear();c2=newMobile();System.out.println(手机的年销售量：+c2.totalSalesByYear();结果截图：京Ecte