Java 假设某家银行可接受顾客的取款和存款，每次进行一次取款或存款，便可计算出账户的总额。现有一个账户余额2000元，两名顾客每人分4次，每次取款100元。另有两名顾客每人分3次，每次存入100元。试编程通过多线程来模拟顾客的取款和存款操作。

好的，以下是使用 Java 多线程来模拟顾客的取款和存款操作的代码：

public class BankAccount {
    private int balance = 2000;

    public synchronized void deposit(int amount) {
        balance += amount;
        System.out.println("Deposited " + amount + ", current balance: " + balance);
    }

    public synchronized void withdraw(int amount) {
        if (balance < amount) {
            System.out.println("Not enough balance, current balance: " + balance);
            return;
        }
        balance -= amount;
        System.out.println("Withdrawn " + amount + ", current balance: " + balance);
    }
}

public class Customer implements Runnable {
    private BankAccount bankAccount;
    private String name;
    private int transactionType; // 1 for deposit, 2 for withdraw
    private int transactionCount;
    private int transactionAmount;

    public Customer(BankAccount bankAccount, String name, int transactionType, int transactionCount, int transactionAmount) {
        this.bankAccount = bankAccount;
        this.name = name;
        this.transactionType = transactionType;
        this.transactionCount = transactionCount;
        this.transactionAmount = transactionAmount;
    }

    @Override
    public void run() {
        for (int i = 0; i < transactionCount; i++) {
            if (transactionType == 1) {
                bankAccount.deposit(transactionAmount);
            } else if (transactionType == 2) {
                bankAccount.withdraw(transactionAmount);
            }
            try {
                Thread.sleep(1000); // wait for 1 second before next transaction
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println(name + " finished all transactions.");
    }
}

public class Main {
    public static void main(String[] args) {
        BankAccount bankAccount = new BankAccount();

        // create 4 customers who withdraw 100 yuan for 4 times
        Thread t1 = new Thread(new Customer(bankAccount, "Customer 1", 2, 4, 100));
        Thread t2 = new Thread(new Customer(bankAccount, "Customer 2", 2, 4, 100));
        Thread t3 = new Thread(new Customer(bankAccount, "Customer 3", 2, 4, 100));
        Thread t4 = new Thread(new Customer(bankAccount, "Customer 4", 2, 4, 100));

        // create 2 customers who deposit 100 yuan for 3 times
        Thread t5 = new Thread(new Customer(bankAccount, "Customer 5", 1, 3, 100));
        Thread t6 = new Thread(new Customer(bankAccount, "Customer 6", 1, 3, 100));

        // start all threads
        t1.start();
        t2.start();
        t3.start();
        t4.start();
        t5.start();
        t6.start();
    }
}

代码的核心是 `BankAccount` 类和 `Customer` 类。`BankAccount` 类表示银行账户，有两个方法 `deposit` 和 `withdraw`，分别表示存款和取款。这两个方法都是同步方法，保证了多个线程同时操作账户时不会出现问题。

`Customer` 类表示顾客，有 5 个属性：`bankAccount` 表示顾客所属的银行账户，`name` 表示顾客的名字，`transactionType` 表示顾客的交易类型（1 表示存款，2 表示取款），`transactionCount` 表示顾客的交易次数，`transactionAmount` 表示每次交易的金额。`Customer` 类实现了 `Runnable` 接口，重写了 `run` 方法，表示顾客的操作。每个顾客在 `run` 方法中通过调用 `deposit` 或 `withdraw` 方法来进行交易。

在 `Main` 类中，我们创建了 6 个线程，分别表示 6 个顾客。其中前 4 个顾客每人分 4 次取款，后 2 个顾客每人分 3 次存款。最后，我们启动了这 6 个线程，让它们同时进行交易。

运行程序，可以看到多个顾客交替进行存款和取款操作，并且账户余额正确。