Java基础之：OOP——多态练习题
应用案例1：
编写教师类
要求有属性“姓名name”，“年龄age”，“职称post”，“基本工资salary”
编写业务方法， introduce（），实现输出一个教师的信息。
编写教师类的三个子类：教授类(professor)、副教授类(vice professor)、讲师类(lecturer)。
工资级别分别为：教授为1.3、副教授为1.2、讲师类1.1。在三个子类里面都重写父类的introduce（）方法。
定义并初始化一个老师对象，调用业务方法，实现对象基本信息的后台打印。
package polymorphic_HomeWork;
public class WorkTest_01 {
public static void main(String[] args) {
Teacher professor = new Professor("小范",20,"professor",4000.0);
Teacher viceProfessor = new ViceProfessor("小黄",18,"ViceProfessor",3000.0);
Teacher lecturer = new Lecturer("小雨",19,"lecturer",2000.0);
System.out.println(professor.introduce());
System.out.println(viceProfessor.introduce());
System.out.println(lecturer.introduce());
}
}
//要求有属性“姓名name”，“年龄age”，“职称post”，“基本工资salary”，
//编写业务方法， introduce（），实现输出一个教师的信息。
class Teacher{
private String name;
private int age;
private String post;
private double salary;
public Teacher(String name, int age, String post, double salary) {
super();
this.name = name;
this.age = age;
this.post = post;
this.salary = salary;
}
public Teacher() {
super();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getPost() {
return post;
}
public void setPost(String post) {
this.post = post;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
//introduce（），实现输出一个教师的信息。
public String introduce() {
return "Teacher [name=" + name + ", age=" + age + ", post=" + post ;
}
}
//教授类(professor)
class Professor extends Teacher{
private double level;
public Professor(String name, int age, String post, double salary) {
super(name, age, post, salary);
this.level = 1.3;
}
public double getLevel() {
return level;
}
public void setLevel(double level) {
this.level = level;
}
@Override
public String introduce() {
// TODO Auto-generated method stub
return "Professor " + super.introduce() + ", salary=" + getSalary()*level + "]";
}
}
//副教授类（vice professor）
class ViceProfessor extends Teacher{
private double level;
public ViceProfessor(String name, int age, String post, double salary) {
super(name, age, post, salary);
this.level = 1.2;
}
public double getLevel() {
return level;
}
public void setLevel(double level) {
this.level = level;
}
@Override
public String introduce() {
// TODO Auto-generated method stub
return "ViceProfessor " + super.introduce() + ", salary=" + getSalary()*level + "]";
}
}
//讲师类（lecturer）
class Lecturer extends Teacher{
private double level;
public Lecturer(String name, int age, String post, double salary) {
super(name, age, post, salary);
this.level = 1.1;
}
public double getLevel() {
return level;
}
public void setLevel(double level) {
this.level = level;
}
@Override
public String introduce() {
// TODO Auto-generated method stub
return "Lecturer " + super.introduce() + ", salary=" + getSalary()*level + "]";
}
}
应用案例2：
设计父类—员工类。子类：工人类(Worker),农民类(Peasant),教师类(Teacher),科学家类(Scientist),服务生类(Waiter)。
（1） 其中工人,农民,服务生只有基本工资。
（2） 教师除基本工资外,还有课酬(元/天)。
（3） 科学家除基本工资外,还有年终奖(bonus)。
（4） 编写一个测试类,将各种类型的员工的全年工资打印出来。
package polymorphic_HomeWork;
public class WorkTest_02 {
public static void main(String[] args) {
Employee worker = new Worker("工人 小范",20,2000);
Employee peasant = new Peasant("农民 小范",40,1000);
Employee waiter = new Waiter("服务生 小范",25,3000);
Employee teacher = new Teacher("老师 小范",30,4000,50,200);
Employee Scientist = new Scientist("科学家 小范",35,3500,250000);
//这里创建的对象的编译类型都是Employee
// System.out.println(worker.toString());
// System.out.println(peasant.toString());
// System.out.println(waiter.toString());
// System.out.println(teacher.toString());
// System.out.println(Scientist.toString());
WorkTest_02 wt = new WorkTest_02();
wt.showAll(Scientist);
wt.showAll(teacher);
wt.showAll(waiter);
wt.showAll(peasant);
wt.showAll(worker);
}
public void showAll(Employee e) { //当有对象传入时，它的编译类型就变为了Employee。
//由于子类重写了父类的show方法，而这里e的运行类型是动态绑定了的。
//所以会自动的寻找到传入类型所对应的show方法
//父类的show方法，相当于让编译器可以通过编译。如果父类中没有show方法会报语法错误。
//因为e的编译类型为Employee.
e.show();
}
}
class Employee{
private String name;
private int age;
private double salary;
public Employee(String name, int age, double salary) {
super();
this.name = name;
this.age = age;
this.salary = salary;
}
public Employee() {
super();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
public void show() {
System.out.println(toString());
}
@Override
public String toString() {
return "name=" + name + ", age=" + age;
}
//提供一个方法返回基本年薪，子类可以在此基础上进行修改
public double yearSalary() {
return salary * 12;
}
}
//工人类(Worker)
class Worker extends Employee{
public Worker(String name, int age, double salary){
super(name,age,salary);
}
@Override
public void show() {
System.out.println("Worker : " + super.toString() + ", salary: " + yearSalary());
}
}
//农民类(peasant)
class Peasant extends Employee{
public Peasant(String name, int age, double salary){
super(name,age,salary);
}
@Override
public void show() {
System.out.println("Peasant : " + super.toString() + ", salary: " + yearSalary());
}
}
//服务生类(waiter)
class Waiter extends Employee{
public Waiter(String name, int age, double salary){
super(name,age,salary);
}
@Override
public void show() {
System.out.println("Waiter : " + super.toString() + ", salary: " + yearSalary());
}
}
//教师类(teacher),教师除基本工资外,还有课酬(元/天)。
class Teacher extends Employee{
private double dollars; //课酬
private int workDays; //工作天数
public Teacher(String name, int age, double salary, double dollars, int workDays) {
super(name, age, salary);
this.dollars = dollars;
this.workDays = workDays;
}
public int getWorkDays() {
return workDays;
}
public void setWorkDays(int workDays) {
this.workDays = workDays;
}
public double getDollars() {
return dollars;
}
public void setDollars(double dollars) {
this.dollars = dollars;
}
@Override
public void show() {
System.out.println( "Teacher : " + super.toString() +
", salary: " + (yearSalary()+dollars*workDays));
}
}
//科学家类(scientist), 科学家除基本工资外,还有年终奖(bonus)。
class Scientist extends Employee{
private double bonus;
public Scientist(String name, int age, double salary, double bonus) {
super(name, age, salary);
this.bonus = bonus;
}
public double getBonus() {
return bonus;
}
public void setBonus(double bonus) {
this.bonus = bonus;
}
@Override
public void show() {
System.out.println("Scientist : " + super.toString() +
",salary:" + (yearSalary()+bonus));
}
}
应用案例3：
定义一个图形类Picture，再定义Picture的两个子类：圆形类Circle、矩形类Rect。 要求： 图像类：有求周长和求面积和显示图形信息的功能。 圆形类：包含圆心和半径，重写求周长和求面积的方法。 矩形类：包含长和宽，重写求周长和求面积的方法。
package polymorphic_HomeWork;
public class WorkTest_03 {
public static void main(String[] args) {
Picture circle = new Circle("2,2",3.1);
Picture rect = new Rect(6.4,5.3);
circle.show();
rect.show();
}
}
//图像类：有求周长和求面积和显示图形信息的功能。
class Picture{
private double sideLength; //边长
private int sideCount; //边数
public Picture(double sideLength, int sideCount) {
super();
this.sideLength = sideLength;
this.sideCount = sideCount;
}
public Picture() {
super();
}
public double getSideLength() {
return sideLength;
}
public void setSideLength(double sideLength) {
this.sideLength = sideLength;
}
public int getSideCount() {
return sideCount;
}
public void setSideCount(int sideCount) {
this.sideCount = sideCount;
}
public double perimeter(){ //求周长
return sideCount * sideLength;
}
public double area() { //求面积
return 0.0;
}
public void show() {
System.out.printf("周长(perimeter)：%.2f\t面积(area):%.2f\n",perimeter(),area());
}
}
//圆形类Circle：包含圆心和半径，重写求周长和求面积的方法。
class Circle extends Picture{
private String centerCircle; //圆心:"X,Y"
private double radius; //半径
public Circle(String centerCircle, double radius) {
super();
this.centerCircle = centerCircle;
this.radius = radius;
}
public String getCenterCircle() {
return centerCircle;
}
public void setCenterCircle(String centerCircle) {
this.centerCircle = centerCircle;
}
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}
@Override
public double perimeter(){ //求周长
return 2 * radius * Math.PI;
}
@Override
public double area() { //求面积
return radius * radius * Math.PI;
}
@Override
public void show() {
System.out.printf("Circle：圆心为 ：%S ",centerCircle);
super.show();
}
}
//矩形类Rect：包含长和宽，重写求周长和求面积的方法。
class Rect extends Picture{
private double length;//长
private double wide;//宽
public Rect( double length, double wide) {
super();
this.length = length;
this.wide = wide;
}
public double getLength() {
return length;
}
public void setLength(double length) {
this.length = length;
}
public double getWide() {
return wide;
}
public void setWide(double wide) {
this.wide = wide;
}
@Override
public double perimeter(){ //求周长
return 2 * length + 2 * wide;
}
@Override
public double area() { //求面积
return length * wide;
}
@Override
public void show() {
System.out.print("Rect： ");
super.show();
}
}
