java - while 循环在提示前执行一次

Question

这是一个很难研究的问题，所以如果这是重复的，请原谅我。

基本上，我有一个 while 循环，它只会在用户扫描的代码是整数时中断。我通过尝试 Integer.parseInt(integer) 来检查这一点，并且仅在未抛出 NumberFormatException 时才中断循环。

我的问题是，当循环第一次执行时，抛出异常，没有任何用户输入。

这是我的代码:

Scanner input = new Scanner(System.in);

while (true) 
{
    System.out.print("Please scan barcode: ");
    int inCode = 0;

    try
    {
        inCode = Integer.parseInt(input.next());
    }
    catch (NumberFormatException e)
    {
        System.out.println("Numbers only, please.");
    }

    if (inCode != 0) {
    // Do Stuff
    } else {
    System.out.println("Code can't be zero!");
    }
}

应该发生什么，是这样的:

Please scan barcode: // And here they enter the barcode

但是这会发生:

Please scan barcode: Numbers only, please.
Please scan barcode:

编辑:

根据 Bohemian 的回答，我在代码中添加了 continue 关键字。这解决了问题，但只解决了一半。根据搁置我的问题的人的要求(有充分的理由，正如我现在看到的那样)，我会为你们发布一个 SSCCE。不过，我将删除与数据库接口(interface)的方法，只保留有问题的路径:根据代码创建一个新帐户。

Scanner input = new Scanner(System.in);

while (true)
{
        System.out.print("Please scan barcode: ");
        int inCode = 0;

        try
        {
            inCode = Integer.parseInt(input.next());
        }
        catch (NumberFormatException e)
        {
            System.out.println("Numbers only, please.");
            continue;
        }

        if (true) // Here it checks if an account associated with the code entered exists in the database. Because I'm having issues when it creates a new account, I've made this true.
        {
            System.out.println("No account associated with that code! Create one?");
            System.out.print("(yes/no): ");
            String answer = input.next();
            if (answer.equalsIgnoreCase("yes"))
            {
                System.out.println("Alright.");
                System.out.print("Please enter a name: ");
                String name = input.next();
                System.out.print("Alright. Now I'll add that to the database... ");

                // Here I add that to the database. Omitted.

                System.out.println("Done! Please scan again to interface.");
            }
            else if (answer.equalsIgnoreCase("no"))
            {
                System.out.println("Okay then.");
            }
            else
            {
                System.out.println("Defaulting to no.");
            }
        }
}
// I still haven't written the code to interface with the account.

现在发生的是，它说(在第一次迭代中)

Please scan barcode:

但是，在完成添加帐户的过程后，它再次循环并说:

Please scan barcode: Numbers only, please.
Please scan barcode:

编辑:

请注意，所有内容都在 while 循环中，因此当用户完成所有操作后，它将返回:

Please scan barcode:

Answer 1

我想你想要的是这个:

Scanner input = new Scanner(System.in);
while (true) {

    System.out.print("Please scan barcode: ");
    int inCode = 0;

    try {
        inCode = Integer.parseInt(input.next());
        if (inCode != 0) {
            // Do Stuff
            break;
        }
    } catch (NumberFormatException e) {
        System.out.println("Numbers only, please.");
    }
}