银行数据库类的创建，满足以下条件

1.为银行数据库设计一个类。数据库应支持以下操作：

将一定金额存入账户

从账户中提取一定金额

返回指定帐户中的金额（即余额）的值

将金额从一个帐户转移到另一个帐户

2. 编写一个应用程序类银行帐户应用程序来测试银行帐户，

即创建多个实例并调用BankAccount的每个方法。

1、操作类：BankAccount类

package cn.bdqn.demo02;

public class BankAccount {

    // 定义账户、余额属性
    private String cardId;
    private int balance;

    // 添加无参构造
    public BankAccount() {
    }

    // 添加有参构造
    public BankAccount(String cardId, int balance) {
        this.cardId = cardId;
        this.balance = balance;
    }

    // 添加get/set方法
    public String getCardId() {
        return cardId;
    }

    public void setCardId(String cardId) {
        this.cardId = cardId;
    }

    public int getBalance() {
        return balance;
    }

    public void setBalance(int balance) {
        this.balance = balance;
    }

    // 存款：将一定金额存入账户
    public void deposit(int money) {
        int balance = this.balance;
        this.balance = balance + money;
        System.out.println("存款成功，当前账户余额为" + this.balance + "元");
    }

    // 取款：实现从账户中提取一定金额的功能
    public void withdraw(int money) {
        int balance = this.balance;
        if (balance >= money) {
            this.balance = balance - money;
            System.out.println("取款成功，当前账户余额为" + this.balance + "元");
        } else if (balance < money) {
            System.out.println("取款失败，您的余额不足");
        }
    }

    // 转账：实现将金额从一个帐户转移到另一个帐户的功能
    public void transfer(BankAccount bankAccount) {
        if (balance > 0) {
            this.balance = bankAccount.getBalance() + this.balance;
            bankAccount.setBalance(0);
            System.out.println("转账成功，"+this.getCardId()+"余额为" + this.balance + "元");
            System.out.println("转账成功，"+bankAccount.getCardId()+"余额为" + bankAccount.getBalance() + "元");
        } else {
            System.out.println("转账失败，您的余额不足");
        }
    }
}

2、测试类：BankTest类

package cn.bdqn.demo02;

public class BankTest {

    public static void main(String[] args) {

        //初始化两张银行卡卡号和余额
        BankAccount account1 = new BankAccount("6227****3301", 1000);
        BankAccount account2 = new BankAccount("6227****2533", 2000);
        
        //向account1银行卡存入500
        account1.deposit(500);
        //从account2银行卡取出800
        account2.withdraw(800);
        //将account1银行卡的钱转账到account2银行卡中
        account2.transfer(account1);

    }

}

3、效果：

你这个应该算是银行账户类，我给你看个示例，你可以照这样写

public class BankAccount {
    
    /** 账户id */
    private String id;
    /** 余额 */
    private Integer balance;

    public BankAccount() {
    }

    public BankAccount(String id, Integer balance) {
        this.id = id;
        this.balance = balance;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    // 返回账户中的金额的值
    public Integer getBalance() {
        return balance;
    }
    public void setBalance(Integer balance) {
        this.balance = balance;
    }

    // 存款：将一定金额存入账户
    public void deposit(Integer money) {
        Integer balance = this.balance;
        this.balance = balance + money;
        System.out.println("存款成功，当前账户余额为" + this.balance);
    }
    // 取款：实现从账户中提取一定金额的功能
    public void withdraw(Integer money) {
        Integer balance = this.balance;
        if(balance >= money) {
            this.balance = balance - money;
            System.out.println("取款成功，当前账户余额为" + this.balance);
        } else if(balance < money) {
            System.out.println("取款失败，您的余额不足");
        }
    }
    // 转账：实现将金额从一个帐户转移到另一个帐户的功能
    public void transfer(BankAccount bankAccount) {
        Integer balance = bankAccount.getBalance();
        if(balance > 0) {
            this.balance = balance + this.balance;
            bankAccount.setBalance(0);
            System.out.println("转账成功，当前账户余额为" + bankAccount.getBalance());
        } else {
            System.out.println("转账失败，您的余额不足");
        }
    }
    
    // 测试方法
    public static void main(String[] args) {
        BankAccount account1 = new BankAccount("123a", 34);
        BankAccount account2 = new BankAccount("246b", 134);
        account1.withdraw(50);
        account2.transfer(account2);
    }

}

详细可参考
https://blog.csdn.net/Dershy_/article/details/123510406