用Java写一个ATM柜员模拟项目，需要有的功能有取款、存款、转账、查询余额、历史记录查询、修改密码和退出等功能；其中取款、存款和转账的金额是100的倍数

好的，我可以给你提供一个大概的项目框架，让你参考一下。

首先，你需要创建一个ATM类来处理所有的操作。在ATM类中，你需要定义一些属性，如账户余额、密码等等。你还需要写一些方法实现ATM的各种操作，如取款、存款、转账、查询余额、历史记录查询、修改密码和退出等功能。

下面是一个简单的ATM类示例代码：

import java.util.ArrayList;
import java.util.Scanner;

public class ATM {
    private String accountNumber;
    private String password;
    private double balance;
    private ArrayList<String> transactionHistory;

    public ATM(String accountNumber, String password, double balance) {
        this.accountNumber = accountNumber;
        this.password = password;
        this.balance = balance;
        this.transactionHistory = new ArrayList<>();
    }

    public void withdraw(double amount) {
        if (amount % 100 != 0) {
            System.out.println("金额必须是100的倍数！");
            return;
        }
        if (amount > balance) {
            System.out.println("余额不足！");
            return;
        }
        balance -= amount;
        transactionHistory.add("取款：" + amount);
        System.out.println("取款成功！");
    }

    public void deposit(double amount) {
        if (amount % 100 != 0) {
            System.out.println("金额必须是100的倍数！");
            return;
        }
        balance += amount;
        transactionHistory.add("存款：" + amount);
        System.out.println("存款成功！");
    }

    public void transfer(ATM target, double amount) {
        if (amount % 100 != 0) {
            System.out.println("金额必须是100的倍数！");
            return;
        }
        if (amount > balance) {
            System.out.println("余额不足！");
            return;
        }
        balance -= amount;
        target.balance += amount;
        transactionHistory.add("转账：" + amount + " 给 " + target.accountNumber);
        System.out.println("转账成功！");
    }

    public void checkBalance() {
        System.out.println("账户余额：" + balance);
    }

    public void checkTransactionHistory() {
        System.out.println("交易记录：");
        for (String transaction : transactionHistory) {
            System.out.println(transaction);
        }
    }

    public void changePassword() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入原密码：");
        String oldPassword = scanner.next();
        if (!oldPassword.equals(password)) {
            System.out.println("原密码输入错误！");
            return;
        }
        System.out.println("请输入新密码：");
        String newPassword = scanner.next();
        System.out.println("请再次输入新密码：");
        String newPassword2 = scanner.next();
        if (!newPassword.equals(newPassword2)) {
            System.out.println("两次输入的密码不一致！");
            return;
        }
        password = newPassword;
        System.out.println("密码修改成功！");
    }

    public static void main(String[] args) {
        ATM atm = new ATM("123456", "123456", 1000);
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1.取款  2.存款  3.转账  4.查询余额  5.查询历史记录  6.修改密码  7.退出");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    System.out.println("请输入取款金额：");
                    double withdrawAmount = scanner.nextDouble();
                    atm.withdraw(withdrawAmount);
                    break;
                case 2:
                    System.out.println("请输入存款金额：");
                    double depositAmount = scanner.nextDouble();
                    atm.deposit(depositAmount);
                    break;
                case 3:
                    System.out.println("请输入转账账号：");
                    String targetAccountNumber = scanner.next();
                    System.out.println("请输入转账金额：");
                    double transferAmount = scanner.nextDouble();
                    ATM target = new ATM(targetAccountNumber, "", 0);
                    atm.transfer(target, transferAmount);
                    break;
                case 4:
                    atm.checkBalance();
                    break;
                case 5:
                    atm.checkTransactionHistory();
                    break;
                case 6:
                    atm.changePassword();
                    break;
                case 7:
                    System.out.println("退出系统！");
                    return;
                default:
                    System.out.println("输入有误，请重新输入！");
            }
        }
    }
}

这只是一个简单的示例代码，你可以根据自己的需求进行修改和完善。