Question

我正在制作一个程序来读取while循环中每个用户的输入响应，以检查该年是否是闰年。当我运行它时，控制台告诉我：

线程“main”中的异常java.util.NoSuchElementException

这意味着什么？如何解决问题以使其运行？

import java.util.Scanner;

public class GregorianCalendar {

    public static void main(String[] args) {

        int year, count, num;

        //How many different years to look at
        System.out.println("How many different years would you like to examine?"); 
        Scanner scan = new Scanner(System.in);
        count = scan.nextInt();
        scan.close();

        //Number of iterations
        num = 0;

        while (count != num) 
        {
            num++;

            System.out.println("Enter year");
            Scanner keyboard = new Scanner(System.in);
            year = keyboard.nextInt();
            keyboard.close();

            if (year % 400 == 0 || year % 4 == 0 && year % 100 != 0 && year > 1582) {
                System.out.println(year + " is a leap year!");
            }

            else if (year % 100 == 0 && year % 400 != 0 || year % 100 != 0 && year > 1582) {
                System.out.println(year + " is not a leap year!");
            }

            else {
            System.out.println("Error! " + year + " cannot be before the year 1582!");

            }
        }
    }
}

Answer 1

您遇到的问题是您正在关闭扫描仪，因此您将获得异常。试试这个：

public static void main(String[] args) {

        int year, count, num;

        //How many different years to look at
        System.out.println("How many different years would you like to examine?"); 
        Scanner scan = new Scanner(System.in);
        count = scan.nextInt();

        //Number of iterations
        num = 0;

        while (count != num) 
        {
            num++;

            System.out.println("Enter year");
            year = scan.nextInt();

            if (year % 400 == 0 || year % 4 == 0 && year % 100 != 0 && year > 1582) {
                System.out.println(year + " is a leap year!");
            }

            else if (year % 100 == 0 && year % 400 != 0 || year % 100 != 0 && year > 1582) {
                System.out.println(year + " is not a leap year!");
            }

            else {
            System.out.println("Error! " + year + " cannot be before the year 1582!");

            }
        }

        scan.close();

    }

我还建议在代码中只使用一台扫描仪。

使用Scanner和System.in的NoSuchElementException

1 个答案: