如何在Java中建模一定数量的Money

import java.math.BigDecimal;

public class Money {
    private BigDecimal amount;

    public Money(BigDecimal amount) {
        this.amount = amount;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public Money add(Money money) {
        return new Money(this.amount.add(money.getAmount()));
    }

    public Money subtract(Money money) {
        return new Money(this.amount.subtract(money.getAmount()));
    }

    public Money multiply(BigDecimal multiplier) {
        return new Money(this.amount.multiply(multiplier));
    }

    public Money divide(BigDecimal divisor) {
        return new Money(this.amount.divide(divisor));
    }

    @Override
    public String toString() {
        return amount.toString();
    }
}

import java.math.BigDecimal;

public class Main {
    public static void main(String[] args) {
        Money money1 = new Money(new BigDecimal("10.50"));
        Money money2 = new Money(new BigDecimal("5.25"));

        Money sum = money1.add(money2);
        System.out.println("Sum: " + sum);

        Money difference = money1.subtract(money2);
        System.out.println("Difference: " + difference);

        Money product = money1.multiply(new BigDecimal("2"));
        System.out.println("Product: " + product);

        Money quotient = money1.divide(new BigDecimal("2"));
        System.out.println("Quotient: " + quotient);
    }
}

Sum: 15.75
Difference: 5.25
Product: 21.00
Quotient: 5.25