package lianxi4;public abstract class Employee {  private String name;  private int number;  private MyDate birthday;public String getName() {    return name;}public void setName(String name) {    this.name = name;}public int getNumber() {    return number;}public void setNumber(int number) {    this.number = number;}public MyDate getBirthday() {    return birthday;}public void setBirthday(MyDate birthday) {    this.birthday = birthday;}public Employee(String name, int number, MyDate birthday) {    super();    this.name = name;    this.number = number;    this.birthday = birthday;}public abstract double earnings();@Overridepublic String toString() {    return "birthday=" + birthday.toDateString() + ", name=" + name + ", number="            + number + "]";}}

package lianxi4;public class MyDate {   private int month;   private int day;   private int year;public MyDate(int month, int day, int year) {    super();    this.month = month;    this.day = day;    this.year = year;}public int getMonth() {    return month;}public void setMonth(int month) {    this.month = month;}public int getDay() {    return day;}public void setDay(int day) {    this.day = day;}public int getYear() {    return year;}public void setYear(int year) {    this.year = year;}public String toDateString(){    return this.year+"年"+this.month+"月"+this.day+"日";}}

package lianxi4;public class SalariedEmployee extends Employee{private double monthlySalary;public SalariedEmployee(String name, int number, MyDate birthday,double monthlySalary){    super(name,number,birthday);    this.monthlySalary = monthlySalary;}@Overridepublic double earnings() {    return monthlySalary;}@Overridepublic String toString() {    return "SalariedEmployee ["+super.toString()+"monthlySalary=" + monthlySalary + "]";}}

package lianxi4;import java.util.Scanner;public class PayrollSystem {    public static void main(String[] args) {        Employee []emps = new Employee[2];  //注意，虽然Employee是抽象类，但是是定义数组，不是实例化        emps[0] = new SalariedEmployee("小明",1001,new MyDate(5,3,1990),4000);//体现多态性        emps[1] = new HourlyEmployee("小红",1002,new MyDate(4,12,1993),20,8);                Scanner s = new Scanner(System.in);        System.out.println("请输入当前月份");        int month = s.nextInt();        for(int i=0;i< emps.length;i++){            System.out.println(emps[i]);            if(month==emps[i].getBirthday().getMonth()){                System.out.println("增加"+emps[i].getName()+"工资100元");                            }        }    }}