实例需求：实现一个名为Person的类和它的子类Employee，Manager是Employee的子类，设计一 个类Add()用于涨工资，普通员工一次能涨10%，经理能涨20%。

具体要求如下:

(1)Person类中的属性有：姓名name String(类型)，地址address(String类型)，定义该类的构造方法；(2)Employee 类中的属性有：工号ID(String类型)，工资wage(double类型)，工龄(int 型)，定义该类的构造方法；

(3)Manager类中的属性有：级别level(String类型)定义该类的构造方法；

(4)编写一个测试类，产生一个员工和一个经理，给该员工和经理涨工资。

1、利用继承的特性

当子类没有相应的成员方法时，调用父类的同名方法。

Person.java

package person_employee;

public class Person {

private String name = "";

private String address = "";

//定义构造方法

public Person(String name, String address){

this.name = name;

this.address = address;

}

}

Employee.java

package person_employee;

// 继承Person类

public class Employee extends Person {

private String ID = "";

private double wage = 0;

private int age = 0;

public Employee(String name, String address, String ID, double wage, int age){

super(name, address); //调用父类的构造方法

this.ID = ID;

this.wage = wage;

this.age = age;

}

public double add(String position){// 判断职位

if(position == "0"){

wage = wage*1.2;

}

else{

wage = wage*1.1;

}

return wage;

}

//设置get/set方法

public double getWage() {

return wage;

}

public void setWage(double wage) {

this.wage = wage;

}

}

Manager.java

package person_employee;

//继承Employee类

public class Manager extends Employee{

private String level = ""; //1为普通员工，0为经理

public Manager(String name, String address, String ID, double wage, int age, String level){

super(name, address, ID, wage, age);

this.level = level;

}

//设置get/set方法

public String getLevel() {

return level;

}

public void setLevel(String level) {

this.level = level;

}

}

Test.java

package person_employee;

public class Test {

public static void main(String[] args) {

// 新建对象

Manager normal = new Manager("wsl", "jit", "12", 1000, 2, "1");

Manager manager = new Manager("ctl", "jitt", "123", 10000, 10, "0");

// 传入职位，Manager类型的对象没有add()方法，所以自动搜寻其父类，调用add()方法

normal.add(normal.getLevel());

manager.add(manager.getLevel());

System.out.println("normal wage is:"+normal.getWage());

System.out.println("manager wage is:"+manager.getWage());

}

}

打印结果：

打印结果

2、定义抽象类

定义抽象类，在子类中实现不同的抽象方法。

Person.java

package person_employee;

public class Person {

private String name = "";

private String address = "";

//定义构造方法

public Person(String name, String address){

this.name = name;

this.address = address;

}

}

Employee.java

package person_employee;

public abstract class Employee extends Person {

private String ID = "";

private double wage = 0;

private int age = 0;

public Employee(String name, String address, String ID, double wage, int age){

super(name, address);

this.ID = ID;

this.wage = wage;

this.age = age;

}

//定义抽象方法

public abstract void add(String position);

//设置get/set方法

public double getWage() {

return wage;

}

public void setWage(double wage) {

this.wage = wage;

}

}

Manager.java

package person_employee;

public class Manager extends Employee{

private String level = "";

public Manager(String name, String address, String ID, double wage, int age, String level){

super(name, address, ID, wage, age);

this.level = level;

}

//实现抽象方法

public void add(String position){

double wage = super.getWage();

if(position == "0"){

super.setWage(wage*1.2);

}

else{

super.setWage(wage*1.1);;

}

}

public String getLevel() {

return level;

}

public void setLevel(String level) {

this.level = level;

}

}

Test.java

package person_employee;

public class Test {

public static void main(String[] args) {

Manager normal = new Manager("wsl", "jit", "12", 1000, 2, "1");

Manager manager = new Manager("ctl", "jitt", "123", 10000, 10, "0");

normal.add(normal.getLevel());

manager.add(manager.getLevel());

System.out.println("normal wage is:"+normal.getWage());

System.out.println("manager wage is:"+manager.getWage());

}

}

打印结果一样。

3、在2的基础上利用多态实现方法的重载

Manager.java

package person_employee;

public class Manager extends Employee{

private String level = "";

public Manager(String name, String address, String ID, double wage, int age, String level){

super(name, address, ID, wage, age);

this.level = level;

}

//实现抽象方法

public void add(){

double wage = super.getWage();

super.setWage(wage*1.1);

}

public void add(String position){

double wage = super.getWage();

super.setWage(wage*1.2);

}

public String getLevel() {

return level;

}

public void setLevel(String level) {

this.level = level;

}

}

Test.java

package person_employee;

public class Test {

public static void main(String[] args) {

Manager normal = new Manager("wsl", "jit", "12", 1000, 2, "1");

Manager manager = new Manager("ctl", "jitt", "123", 10000, 10, "0");

normal.add();

manager.add(manager.getLevel());

System.out.println("normal wage is:"+normal.getWage());

System.out.println("manager wage is:"+manager.getWage());

}

}

打印结果一样