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]);
        }
        
    }
}