JAVA 员工管理系统（用抽象类实现），简易版。

 package Demo513;
 /*
 定义一个Employee类，该类包含：
         private 成员变量name，number，birthday，其中birthday为MyDate类的对象；
         abstract方法earnings（）：toString（）方法输出对象的name，number和birt
  */

 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();

     @Override
     public String toString() {
         return "name="+name+",number"+number+",birthday="
                 +birthday.toString()+"]";
     }
 }

 package Demo513;
 /*
 MyDate类包括：
         private成员变量month，day，year；
         toDateString()方法返回日期对应的字符串：xxxx年xx月xx日
  */
 public class MyDate {
     private int year;
     private int month;
     private int day;

     public MyDate(int year, int month, int day) {
         this.year = year;
         this.month = month;
         this.day = day;
     }
     public String toDateString(){
         return year + "年"+month+"月"+day+"日";
     }

     public int getYear() {
         return year;
     }

     public void setYear(int year) {
         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;
     }
 }

 package Demo513;
 /*
 定义 SalariedEmployee类继承Employee类，实现按月计算工资的员工处理。
    private成员变量monthlySalary；
 实现父类的抽象方法earnings（），该方法返回monthSalary值，toString（）方法输出员工类型信息
 及员工的name，number，birthday。
  */
 public class SalariedEmployee extends Employee{
     private double monthlySalary;//月工资

     public SalariedEmployee(String name,int number,MyDate birthdat,double Salary) {
         super(name,number,birthdat);
         this.monthlySalary = monthlySalary;
     }

     public double earnings(){
         return monthlySalary;
     }

     @Override
     public String toString() {
         return "SalariedEmployee{"+super.toString() +
                 "monthlySalary=" + monthlySalary +
                 '}';
     }
 }

 package Demo513;
 /*
 定义 SalariedEmployee类继承Employee类，实现按月计算工资的员工处理。
    private成员变量monthlySalary；
 实现父类的抽象方法earnings（），该方法返回monthSalary值，toString（）方法输出员工类型信息
 及员工的name，number，birthday。
  */
 public class SalariedEmployee extends Employee{
     private double monthlySalary;//月工资

     public SalariedEmployee(String name,int number,MyDate birthdat,double Salary) {
         super(name,number,birthdat);
         this.monthlySalary = monthlySalary;
     }

     public double earnings(){
         return monthlySalary;
     }

     @Override
     public String toString() {
         return "SalariedEmployee{"+super.toString() +
                 "monthlySalary=" + monthlySalary +
                 '}';
     }
 }

 package Demo513;
 /*
 定义payrollSystem类，创建Employee变量数组并初始化，该数组存放各类雇员对象的引用。
 利用循环结构遍历数组元素。输出各个对象的类型，name，number，birthda，以及对象生日。
 当键盘输入本月月份值是，如果本月是某个Employee对象的生日，还要输出增加工资信息。

  */

 import java.util.Scanner;

 public class PayrollSystem {
     public static void main(String[] args) {
         Employee[] emp = new Employee[2];
         System.out.println();
         emp[0] = new SalariedEmployee("noo", 1001, new MyDate(2000, 9, 16), 4000);
         emp[1] = new SalariedEmployee("hjj", 1002, new MyDate(2000, 12, 31), 5000);
         Scanner scanner=new Scanner(System.in);
         System.out.println("请输入本月的月份：");
         int month =scanner.nextInt();

         for (int i = 0; i < emp.length; i++) {
             if(month==emp[i].getBirthday().getMonth()){
                 System.out.println("加工资100");
             }
             System.out.println(emp[i]);
         }

     }
 }