优化一下，顾客数量也可以自定义

好的，以下是优化后的程序：

import java.util.*;

public class BankAccount {
    private double totalAmount;

    public BankAccount() {
        totalAmount = 0;
    }

    public double getTotalAmount() {
        return totalAmount;
    }

    public void addMoney(double amount) {
        totalAmount += amount;
    }
}

class Customer {
    private String name;
    private double[] amounts;
    private int[] frequencies;
    private BankAccount account;

    public Customer(String name, double[] amounts, int[] frequencies, BankAccount account) {
        this.name = name;
        this.amounts = amounts;
        this.frequencies = frequencies;
        this.account = account;
    }

    public String getName() {
        return name;
    }

    public void doTransfer() {
        Random rand = new Random();
        for (int i = 0; i < amounts.length; i++) {
            if (frequencies[i] == 0) {
                continue;
            }
            double amount = amounts[i];
            account.addMoney(amount);
            frequencies[i]--;
            System.out.println(name + " transferred " + amount + " to bank account");
            try {
                Thread.sleep(rand.nextInt(1000) + 500);
            }
            catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

public class BankSimulation {
    public static void main(String[] args) {
        BankAccount account = new BankAccount();
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter the number of customers: ");
        int numCustomers = scanner.nextInt();
        Customer[] customers = new Customer[numCustomers];
        for (int i = 0; i < numCustomers; i++) {
            System.out.print("Enter the name of customer " + (i + 1) + ": ");
            String name = scanner.next();
            System.out.print("Enter the number of transfers for customer " + (i + 1) + ": ");
            int numTransfers = scanner.nextInt();
            double[] amounts = new double[numTransfers];
            int[] frequencies = new int[numTransfers];
            for (int j = 0; j < numTransfers; j++) {
                System.out.print("Enter the amount for transfer " + (j + 1) + " for customer " + (i + 1) + ": ");
                amounts[j] = scanner.nextDouble();
                frequencies[j] = 1;
            }
            customers[i] = new Customer(name, amounts, frequencies, account);
        }

        int totalTransfers = 0;
        while (true) {
            List<Customer> activeCustomers = new ArrayList<>();
            for (Customer customer : customers) {
                if (Arrays.stream(customer.frequencies).sum() > 0) {
                    activeCustomers.add(customer);
                }
            }
            if (activeCustomers.size() == 0) {
                break;
            }
            Collections.shuffle(activeCustomers);
            for (Customer customer : activeCustomers) {
                customer.doTransfer();
            }
            totalTransfers += activeCustomers.size();
        }

        System.out.println("Total amount transferred: " + account.getTotalAmount());
        System.out.println("Total number of transfers: " + totalTransfers);
    }
}

和之前的程序相比，这个程序增加了一个 `Scanner` 对象，用于从用户输入中读取顾客数量和汇款信息。在 `main()` 方法中，先读取顾客数量，然后循环读取每个顾客的姓名、汇款次数和汇款金额，并创建对应的 `Customer` 对象。

这个程序可以自定义顾客数量和每个顾客的汇款金额和次数，并且能够模拟多个顾客并发汇款的场景。