如何在 Java 中将资金从一个银行账户转移到另一个银行账户？

Question

任务： 更改 Account 类，以便可以将资金从一个帐户转移到另一个帐户。可以将其视为从一个帐户中提取资金并将其存入另一个帐户。更改 Banking 类的 main 方法以显示此新服务。

我正在开发一个可以从银行账户余额中存款和取款的银行账户类。我正在处理任务的类部分，您在其中声明驱动程序的所有方法。我的任务希望我制定一种方法，可以从一个帐户中提取资金并将该资金存入另一个帐户。我已经知道如何取款和存款，只是不知道如何将钱从一个账户转移到另一个账户。到目前为止，这是我的传输方法代码：

import java.text.NumberFormat;
public class Account
{
    private NumberFormat fmt = NumberFormat.getCurrencyInstance();
    private final double RATE = 0.035; // interest rate of 3.5%
    private long acctNumber;
    private double balance;
    private String name;
    //-----------------------------------------------------------------
    // Sets up the account by defining its owner, account number,
    // and initial balance.
    //-----------------------------------------------------------------
    public Account (String owner, long account, double initial)
    {
        name = owner;
        acctNumber = account;
        balance = initial;
    }
    //-----------------------------------------------------------------
    // Validates the transaction, then deposits the specified amount
    // into the account. Returns the new balance.
    //-----------------------------------------------------------------
    public double deposit (double amount)
    {
        if (amount < 0) // deposit value is negative
        {
            System.out.println ();
            System.out.println ("Error: Deposit amount is invalid.");
            System.out.println (acctNumber + " " + fmt.format(amount));
        }
        else
            balance = balance + amount;
        return balance;
    }
    //-----------------------------------------------------------------
    // Validates the transaction, then withdraws the specified amount
    // from the account. Returns the new balance.
    //-----------------------------------------------------------------
    public double withdraw (double amount, double fee)
    {
        amount += fee;
        if (amount < 0) // withdraw value is negative
        {
        System.out.println ();
        System.out.println ("Error: Withdraw amount is invalid.");
        System.out.println ("Account: " + acctNumber);
        System.out.println ("Requested: " + fmt.format(amount));
        }
        else
        if (amount > balance) // withdraw value exceeds balance
        {
        System.out.println ();
        System.out.println ("Error: Insufficient funds.");
        System.out.println ("Account: " + acctNumber);
        System.out.println ("Requested: " + fmt.format(amount));
        System.out.println ("Available: " + fmt.format(balance));
        }
        else
        balance = balance - amount;
        return balance;
    }

    public double transfer (double amount, double fee)
    {
        amount += fee;
        if (amount < 0) // withdraw value is negative
        {
            System.out.println ();
            System.out.println ("Error: Withdraw amount is invalid.");
            System.out.println ("Account: " + acctNumber);
            System.out.println ("Requested: " + fmt.format(amount));
        }
        else
        if (amount > balance) // withdraw value exceeds balance
        {
            System.out.println ();
            System.out.println ("Error: Insufficient funds.");
            System.out.println ("Account: " + acctNumber);
            System.out.println ("Requested: " + fmt.format(amount));
            System.out.println ("Available: " + fmt.format(balance));
        }
        else
            balance = balance - amount;

         //What should I put here to deposit the amount into another account?

        if (amount < 0) // deposit value is negative
        {
            System.out.println ();
            System.out.println ("Error: Deposit amount is invalid.");
            System.out.println (acctNumber + " " + fmt.format(amount));
        }
        else
            balance = balance + amount;
    }

    //-----------------------------------------------------------------
    // Adds interest to the account and returns the new balance.
    //-----------------------------------------------------------------
    public double addInterest ()
    {
        balance += (balance * RATE);
        return balance;
    }
    //-----------------------------------------------------------------
    // Returns the current balance of the account.
    //-----------------------------------------------------------------
    public double getBalance ()
    {
        return balance;
    }
    //-----------------------------------------------------------------
    // Returns the account number.
    //-----------------------------------------------------------------
    public long getAccountNumber ()
    {
        return acctNumber;
    }
    //-----------------------------------------------------------------
    // Returns a one-line description of the account as a string.
    //-----------------------------------------------------------------
    public String toString ()
    {
        return (acctNumber + "\t" + name + "\t" + fmt.format(balance));
    }
}

Answer 1

您的转移方法没有任何目的。 Tranfer 应该是您的主类中实例化帐户的方法。转移的例子是。

public static void main(String[] args)
{
    // This creates two different accounts :)
    Account a = new Account("userA", 123, 200);
    Account b = new Account("userB", 234, 500);

    // Tranfer
    a.withdraw(100, 5);
    System.out.println(a.getBalance());
    b.deposit(100);
    System.out.println(b.getBalance());
}

把它变成一个方法就是

public static void transfer (Account from, Account to, double amount, double fee)
{
    from.withdraw(amount, fee);
    to.deposit(amount);
}

编辑

如果我正确理解了您的第二个问题，您想创建一个默认帐户吗？如果我误解了，你能提供更多细节吗？ （链接到作业或其他东西）

你需要为它写6个新方法，你还没有，

1. getOwner
2. setOwner
3. getAcctNumber
4. setAcctNumber
5. 获取余额
6. 设置平衡

帐户类别

import java.text.NumberFormat;
public class Account
{
    private NumberFormat fmt = NumberFormat.getCurrencyInstance();
    private final double RATE = 0.035; // interest rate of 3.5%
    private long acctNumber;
    private double balance;
    private String name;
    //-----------------------------------------------------------------
    // Sets up the account by defining its owner, account number,
    // and initial balance.
    //-----------------------------------------------------------------
    public Account (String owner, long account, double initial)
    {
        name = owner;
        acctNumber = account;
        balance = initial;
    }
    public Account()
    {
        // This would be the default constructor and default account
        name ="N/A";
        acctNumber = 0;
        balance = 0.0;
    }

    //-----------------------------------------------------------------
    // Validates the transaction, then deposits the specified amount
    // into the account. Returns the new balance.
    //-----------------------------------------------------------------
    public double deposit (double amount)
    {
        if (amount < 0) // deposit value is negative
        {
            System.out.println ();
            System.out.println ("Error: Deposit amount is invalid.");
            System.out.println (acctNumber + " " + fmt.format(amount));
        }
        else
            balance = balance + amount;
        return balance;
    }
    //-----------------------------------------------------------------
    // Validates the transaction, then withdraws the specified amount
    // from the account. Returns the new balance.
    //-----------------------------------------------------------------
    public double withdraw (double amount, double fee)
    {
        amount += fee;
        if (amount < 0) // withdraw value is negative
        {
        System.out.println ();
        System.out.println ("Error: Withdraw amount is invalid.");
        System.out.println ("Account: " + acctNumber);
        System.out.println ("Requested: " + fmt.format(amount));
        }
        else
        if (amount > balance) // withdraw value exceeds balance
        {
        System.out.println ();
        System.out.println ("Error: Insufficient funds.");
        System.out.println ("Account: " + acctNumber);
        System.out.println ("Requested: " + fmt.format(amount));
        System.out.println ("Available: " + fmt.format(balance));
        }
        else
        balance = balance - amount;
        return balance;
    }

    //-----------------------------------------------------------------
    // Adds interest to the account and returns the new balance.
    //-----------------------------------------------------------------
    public double addInterest ()
    {
        balance += (balance * RATE);
        return balance;
    }
    //-----------------------------------------------------------------
    // Returns the current balance of the account.
    //-----------------------------------------------------------------
    public double getBalance ()
    {
        return balance;
    }
    //-----------------------------------------------------------------
    // Returns the account number.
    //-----------------------------------------------------------------
    public long getAccountNumber ()
    {
        return acctNumber;
    }
    //-----------------------------------------------------------------
    // Returns a one-line description of the account as a string.
    //-----------------------------------------------------------------
    public String toString ()
    {
        return (acctNumber + "\t" + name + "\t" + fmt.format(balance));
    }
}

Drvier 类

public class test
{
    public static void main(String[] args)
    {
        // Created here
        Account defaultAccount = new Account();
        Account a = new Account("userA", 123, 200);
        Account b = new Account("userB", 234, 500);

        System.out.println(defaultAccount.getBalance());
        // Tranfer
        a.withdraw(100, 5);
        System.out.println(a.getBalance());
        b.deposit(100);
        System.out.println(b.getBalance());
    }

    public static void transfer (Account from, Account to, double amount, double fee)
    {
        from.withdraw(amount, fee);
        to.deposit(amount);
    }
}

Answer 2

创建一个方法 transfer(String ID, double amount)，利用 deposit(String Id, double amt) 和提款(double amount) 方法来转移资金。