java - 重复扫描仪临时创可贴？ ( java )

Question

所以我有点困惑为什么会发生这种情况，这是我的代码:

public static void main (String[] args)
{
    Scanner kb = new Scanner(System.in);

    do
    {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a time in 24-hour notation: ");
        String time = in.nextLine();

        int colonIndex = time.indexOf(":");
        int hours = Integer.parseInt(time.substring(0, colonIndex));
        int minutes = Integer.parseInt(time.substring(colonIndex + 1));

        boolean legalTime = ((hours < 24 && hours > 0) && (minutes < 60 && minutes >= 0));
        boolean addZero = minutes < 10;
        boolean pm = hours > 12;

        if(legalTime)
        {
            if(pm && addZero)
            {
                int newHour = hours - 12;
                System.out.printf("That is the same as"
                        + "\n%d:0%d PM\n", newHour, minutes);
            }
            else if(pm && !addZero)
            {
                hours = hours - 12;
                System.out.printf("That is the same as"
                        + "\n%d:%d PM\n", hours, minutes);
            }
            else if (!pm && addZero)
            {
                System.out.printf("That is the same as"
                        + "\n%d:0%d AM\n", hours, minutes);
            }
            else
            {
                System.out.printf("That is the same as"
                        + "\n%d:%d AM\n", hours, minutes);
            }
        }
        try
        {
            if(!legalTime)
            {
                throw new Exception("Exception: there is no such time as " + time);
            }
        }
        catch(Exception e)
        {
            System.out.println(e.getMessage()
                    + "\nAgain? (y/n)");
            continue;
        }

        System.out.println("Again? (y/n)");

    }while(Character.toUpperCase(kb.next().charAt(0)) == 'Y');

}

我的代码本身不是问题，而是 do-while 循环的条件仅识别 do-while 之外的 boolean 值，在我看来，这使得使条件受到 do-while 内部任何内容的影响非常令人沮丧堵塞。我想做的是让我的代码运行，然后询问用户是否要再次运行它，用“y”或“n”表示。我不能放

!time.charAt(0) == 'y'

作为条件，因为字符串“time”是在 do-while 循环内定义的，所以我做了一些奇怪的创可贴，使用一个扫描仪仅用于 do-while 开始之前的条件输入，并在内部使用另一个扫描仪 body 。我知道这很糟糕，但我想不出一种简单的方法来为不在 do-while 循环内的这种条件创建 boolean 值，我是否遗漏了一些东西？

Answer 1

只需在循环之前声明一个 boolean 而不是额外的 Scanner，并在循环内更新此 boolean:

boolean again = true;
do {
    ...
    System.out.println("Again? (y/n)");
    again = Character.toUpperCase(in.next().charAt(0)) == 'Y';
} while (again);