为某公司编写一个工资支付系统，用于计算某一类员工的月薪。该公司共有四类员工：领固定月薪的（SalariedEmployee）；计时取酬的（HourlyEmployee，如果一月工时超过160小时，则还需对额外的工时支付加班费）；按销售额提成（CommissionEmployee）的和带底薪并按销售额提成的（BasePlusCommissionEmployee），其继承层次结构如下所示。已知每类员工均有表示员工工号、姓名和出生年月的属性，和用于计算员工月薪的方法。创建一个Employee变量数组，保存Employee类层次结构中每个具体类对象的引用，对每个Employee显示其工号、姓名、出生年月和月收入，如果当月是Employee的生日所在的月份，则还另发给他100月作为红包。 Java

以下是一个针对该需求的Java代码示例：

import java.time.LocalDate;

public class PayrollSystem {
    public static void main(String[] args) {
        // 创建员工数组，包含不同类型的员工对象
        Employee[] employees = new Employee[4];
        employees[0] = new SalariedEmployee("123", "Tom", LocalDate.of(1990, 3, 10), 5000);
        employees[1] = new HourlyEmployee("456", "Jerry", LocalDate.of(1995, 5, 15), 35, 100);
        employees[2] = new CommissionEmployee("789", "Lucy", LocalDate.of(1985, 8, 20), 10000, 0.1);
        employees[3] = new BasePlusCommissionEmployee("101", "Bob", LocalDate.of(1992, 10, 1), 8000, 0.15, 2000);

        // 遍历员工数组，显示每个员工的信息和月收入
        for (Employee employee : employees) {
            System.out.println("Employee ID: " + employee.getId());
            System.out.println("Employee Name: " + employee.getName());
            System.out.println("Employee Birthday: " + employee.getBirthDate());
            double earnings = employee.earnings();
            System.out.println("Employee Monthly Income: " + earnings);
            if (employee.isBirthdayMonth()) {
                System.out.println("Happy Birthday! You got a 100 yuan red envelope!");
                earnings += 100;
                System.out.println("Employee Monthly Income with Red Envelope: " + earnings);
            }
            System.out.println();
        }
    }
}

abstract class Employee {
    private String id;
    private String name;
    private LocalDate birthDate;

    public Employee(String id, String name, LocalDate birthDate) {
        this.id = id;
        this.name = name;
        this.birthDate = birthDate;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public LocalDate getBirthDate() {
        return birthDate;
    }

    // 判断当月是否是员工生日所在月份
    public boolean isBirthdayMonth() {
        LocalDate now = LocalDate.now();
        return now.getMonthValue() == birthDate.getMonthValue();
    }

    // 计算员工月收入，具体实现在各个子类中
    public abstract double earnings();
}

class SalariedEmployee extends Employee {
    private double monthlySalary;

    public SalariedEmployee(String id, String name, LocalDate birthDate, double monthlySalary) {
        super(id, name, birthDate);
        this.monthlySalary = monthlySalary;
    }

    @Override
    public double earnings() {
        return monthlySalary;
    }
}

class HourlyEmployee extends Employee {
    private double hourlyWage;
    private double hoursWorked;

    public HourlyEmployee(String id, String name, LocalDate birthDate, double hourlyWage, double hoursWorked) {
        super(id, name, birthDate);
        this.hourlyWage = hourlyWage;
        this.hoursWorked = hoursWorked;
    }

    @Override
    public double earnings() {
        double basePay = hourlyWage * hoursWorked;
        if (hoursWorked > 160) {
            double overtimePay = (hoursWorked - 160) * hourlyWage * 0.5;
            return basePay + overtimePay;
        } else {
            return basePay;
        }
    }
}

class CommissionEmployee extends Employee {
    private double grossSales;
    private double commissionRate;

    public CommissionEmployee(String id, String name, LocalDate birthDate, double grossSales, double commissionRate) {
        super(id, name, birthDate);
        this.grossSales = grossSales;
        this.commissionRate = commissionRate;
    }

    @Override
    public double earnings() {
        return grossSales * commissionRate;
    }
}

class BasePlusCommissionEmployee extends CommissionEmployee {
    private double baseSalary;

    public BasePlusCommissionEmployee(String id, String name, LocalDate birthDate, double grossSales, double commissionRate, double baseSalary) {
        super(id, name, birthDate, grossSales, commissionRate);
        this.baseSalary = baseSalary;
    }

    @Override
    public double earnings() {
        return super.earnings() + baseSalary;
    }
}

该程序中，Employee类是所有员工类型的抽象父类，其中定义了员工的基本信息和方法。四个具体员工类型分别继承自Employee，并实现了各自特有的earnings方法，用于计算员工月收入。

PayrollSystem类是程序的入口，创建了一个Employee数组，包含了不同类型的员工对象，然后遍历数组，显示每个员工的信息和月收入，如果当月是员工的生日所在的月份，则还另发给员工100元作为红包。