如何在Java编程中模拟银行存款利息计算的过程？

在Java中，模拟银行存款利息计算通常涉及创建一个抽象类或接口`BankAccount`，定义一些基本操作，比如存款、取款和计算利息的方法。然后可以创建具体的子类，如`SavingsAccount`和`CheckingAccount`，分别代表储蓄账户和支票账户，它们可能会有不同的利率规则。

以下是简化的步骤：

1. **定义基础类**:

public abstract class BankAccount {
    private double balance;
    private double interestRate;

    // 构造函数
    public BankAccount(double initialBalance, double rate) {
        this.balance = initialBalance;
        this.interestRate = rate;
    }

    // 抽象方法
    public abstract double calculateInterest();

    // 其他共用方法，如存取款
    public void deposit(double amount) {
        balance += amount;
    }
    public void withdraw(double amount) {
        if (amount <= balance) {
            balance -= amount;
        } else {
            System.out.println("Insufficient funds.");
        }
    }
}

2. **实现具体子类**:

public class SavingsAccount extends BankAccount {
    @Override
    public double calculateInterest() {
        return balance * interestRate / 100; // 计算年化利息
    }
}

public class CheckingAccount extends BankAccount {
    @Override
    public double calculateInterest() {
        // 可能有更低的固定费用或无利息，具体实现根据需求调整
        if (balance < 500) {
            return 0;
        } else {
            return super.calculateInterest();
        }
    }
}

3. **使用子类**:

public static void main(String[] args) {
    SavingsAccount savings = new SavingsAccount(1000, 2);
    savings.deposit(500);
    System.out.printf("After deposit and one year's interest, balance is %.2f\n", savings.balance + savings.calculateInterest());

    CheckingAccount checking = new CheckingAccount(750, 1);
    checking.withdraw(200);
    System.out.printf("After withdrawal, the interest is %.2f\n", checking.calculateInterest());
}