Javascript 如何在java中不重复验证

我正在写一个程序来计算房子里油漆房间的价格。 该程序会向用户询问几个问题，用户必须输入有关该主题的特定答案。在不接受0和负数的情况下，程序还必须实施验证：

  Scanner keyboard = new Scanner(System.in);

  System.out.println("Number of rooms to be painted?");
  noRooms = keyboard.nextDouble();  

  while (noRooms <= 0) {
    System.out.println("Invalid Input for the number of rooms. Please enter in the appropriate number:");
    noRooms = keyboard.nextDouble();    

  System.out.println("Number of sqaure feet of wall space in each room?");
  wallSpace = keyboard.nextDouble();

  while (wallSpace <= 0) {
    System.out.println("Invalid Input for the number of square feet of wall space. Please enter in the appropriate number:");
    wallSpace = keyboard.nextDouble();

---

没有出现错误，但当我输入“正确”或“不正确”数据时，程序不会执行任何操作。还有其他方法调用该方法吗？

我建议您提取一个方法来提示输入值，并调用它两次。大概

static double getValidValue(Scanner sc, String initial, String msg) {
    System.out.println(initial);
    double v = sc.nextDouble();
    while (v <= 0) {
        System.out.printf("Invalid input for the %s. "
                + "Please enter in the appropriate number:%n", msg);
    }
    return v;
}

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

    double noRooms = getValidValue(keyboard,
            "Number of rooms to be painted?", "number of rooms");
    double wallSpace = getValidValue(keyboard,
            "Number of sqaure feet of wall space in each room?",
            "number of square feet of wall space");
    // ... noRooms and wallSpace are > 0.
}

静态双getValidValue（扫描程序sc、字符串首字母、字符串msg）{
系统输出打印项次（首字母）；
双v=sc.nextDouble（）；
而(v 0。
}

有一个方法，它接受扫描仪、提示、错误消息和错误边界，并返回请求的输入。我做了类似的操作，但在运行程序并输入数据时没有显示输出。@user3622970否，您所做的并不完全相似。请注意，在提示输入之前，您忘记打印消息。

private static double validation(Scanner keyboard) {
double v = keyboard.nextDouble();
  while (v <= 0) {
    System.out.println("Invalid Input: Please enter in the appropriate number:");
}
return v;
}

System.out.println("Number of rooms to be painted:");
noRoom= keyboard.nextDouble();
noRoom= validation(keyboard);

static double getValidValue(Scanner sc, String initial, String msg) {
    System.out.println(initial);
    double v = sc.nextDouble();
    while (v <= 0) {
        System.out.printf("Invalid input for the %s. "
                + "Please enter in the appropriate number:%n", msg);
    }
    return v;
}

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

    double noRooms = getValidValue(keyboard,
            "Number of rooms to be painted?", "number of rooms");
    double wallSpace = getValidValue(keyboard,
            "Number of sqaure feet of wall space in each room?",
            "number of square feet of wall space");
    // ... noRooms and wallSpace are > 0.
}