Java 验证用户整数输入

Question

我已经编写了代码

1) 不断要求用户选择数字并检查输入是否为整数

private static int readInputInt(String error) {
    Scanner s = new Scanner(System.in);
    while (!s.hasNextInt()) {
        System.out.println(error);
        s.next();
    }
    int result = s.nextInt();
    //s.close(); 
    return result;
}

2) 不断要求用户选择范围内的数字并仅显示错误，程序不会显示消息要求用户再次提供输入。

private static int readInputInt(String error, int max) {
    Scanner s = new Scanner(System.in);
    int result;
    do {
        while(!s.hasNextInt()) {
            //show error if it is not integer and get input once again
            System.out.println(error);
            s.next();
        }
        result = s.nextInt();
        // if result is integer check if it is bigger than max
        if(result > max) {
            System.out.println(error);
        }

    }while(result > max);

我想知道是否有更简单的方法来做到这一点，因为我为此花费了太多时间，而且我认为这是垃圾编码方式。

首先我认为下面的代码可以工作:

private static int readInputInt(String error, int max) {
    Scanner s = new Scanner(System.in);
    while (!s.hasNextInt() && (s.nextInt < max)) {
        System.out.println(error);
        s.next();
    }
    int result = s.nextInt();
    //s.close(); 
    return result;
}

但它不起作用。如需任何帮助，谢谢!

Answer 1

private static int readInputInt(String error, int max) {
    Scanner s = new Scanner(System.in);
    int result;
    while (true) { 
        if (s.hasNextInt()) {
            result = s.nextInt();    
            if (result <= max) {
                s.close();
                return result;
            }
         } else { //Only want to call next() if it doesn't meet the first conditional. We've already called next when it is an int. 
             s.next();
         }
         System.out.println(error);
    }