Exception in thread "main" java.util.NoSuchElementException

Question

问题遇到的现象和发生背景

Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:862)
at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextInt(Scanner.java:2117)
at java.util.Scanner.nextInt(Scanner.java:2076)
at com.day.numTest.main(numTest.java:11)

问题相关代码，请勿粘贴截图

public class numTest {
        public static void main(String[] args) {
            System.out.println("请输入数字：");
            Scanner input = new Scanner(System.in);
            int num1 = input.nextInt();
            input.close();
            System.out.println(num1);
            Scanner input2 = new Scanner(System.in);
            int num2 = input2.nextInt();
            System.out.println(num2);
            input2.close();
        }
}

Answer 1

用完第一个Scanner关闭了System.in，会 导致第二个Scanenr工具对象不能使用System.in了。

public class numTest {
        public static void main(String[] args) {
            System.out.println("请输入数字：");
            Scanner input = new Scanner(System.in);
            int num1 = input.nextInt();
            System.out.println(num1);
            Scanner input2 = new Scanner(System.in);
            int num2 = input2.nextInt();
            System.out.println(num2);
            input2.close();
        }
}