Java如何创建唯一的对象名称

Question

每当用户想要创建一个新帐户时，我该如何创建一个唯一的对象？

例如，如果用户创建了一个帐户，我想要一个名为acc1的对象，那么如果用户创建其他帐户，我则想要名为acc2的对象。CCD_ 1。这就是我需要它发生的地方。

我试着让代码尽可能简单，同时也注意到我对java相当陌生，这是一个个人项目，只是为了学习。

 System.out.println("Welcome to JAVA Bank");
    System.out.println("____________________");
    System.out.println("Plese Choose an Option: ");
    System.out.println("");
    System.out.println("(1) New Account");
    System.out.println("(2) Enter Existing Account");

    int choice = input.nextInt();

    switch(choice){
        case 1:
            System.out.println("Please choose an Account ID#");
            Account ac = new Account(input.nextInt(),0,0);
            break;


public class Account {
private int id = 0;
private double balance = 0;
private double annualInterestRate = 0;
private Date dateCreated;
public Account(int id, double balance, double annualInterestRate) {
    this.id = id;
    this.balance = balance;
    this.annualInterestRate = annualInterestRate;
    this.dateCreated = new Date();
}

感谢您的帮助。

Answer 1

如果您想要一种独特的方式来识别多个帐户，那么可以使用HashMap。HashMap存储键值对，其中每个键都是唯一的。

创建一个类级变量来存储帐户：

Map<String, Account> accounts = new HashMap<String, Account>();

创建/添加帐户到HashMap:

case 1:
    System.out.println("Please choose an Account ID#");
    int accountID = input.nextInt(); //Get the requested ID
    if (accounts.containsKey("acc"+accountID) //Check to see if an account already has this ID (I added acc to the start of each account but it is optional)
    {
       //Tell user the account ID is in use already and then stop
       System.out.println("Account: " + accountID + " already exists!");
       break;
    }
        //Create account and add it to the HashMap using the unique identifier key
        Account ac = new Account(input.nextInt(),0,0);
        accounts.put("acc"+accountID, ac);