Java如何創建唯一的對象名稱？

Question

每次用戶想要創建新帳戶時，我將如何創建唯一對象？

例如，如果用戶創建一個帳戶，我想要一個名為acc1的對象，那么如果用戶創建另一個帳戶，我想要名為acc2的對象。 Account ac = new Account(input.nextInt(),0,0); 。 這就是我需要它發生的地方。

我盡量保持代碼盡可能簡單，並且還注意到我對java很新，這是一個個人項目，只是為了學習。

 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();

}

感謝您的幫助。

Answer 1

如果您想要一種識別多個帳戶的獨特方式，或許可以使用HashMap。 HashMap存儲每個鍵唯一的鍵值對。

創建一個類級變量來存儲帳戶：

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

創建/添加帳戶到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);