异常：java.util.NoSuchElementException

            Scanner sc = new Scanner(System.in).useDelimiter("\\s");
		int a[] = new int[50];
		int i = 0;
		while (sc.hasNextInt()) {
			a[i++] = sc.nextInt();
		}
		sc.close();
		Scanner sc2 = new Scanner(System.in);
		System.out.println("请输入一个小于" + i + "的数");
		int m = sc2.nextInt();
		sc2.close();

上面这么写就会报java.util.NoSuchElementException异常：

Exception in thread "main" java.util.NoSuchElementException
	at java.util.Scanner.throwFor(Unknown Source)
	at java.util.Scanner.next(Unknown Source)
	at java.util.Scanner.nextInt(Unknown Source)
	at java.util.Scanner.nextInt(Unknown Source)

原因是我们在上面关了System关闭，即对于系统文件关闭了无法再打开，所以就报错了。改的方法很简单，两个Scanner放到最后一块关闭就是了：

            Scanner sc = new Scanner(System.in).useDelimiter("\\s");
		int a[] = new int[50];
		int i = 0;
		while (sc.hasNextInt()) {
			a[i++] = sc.nextInt();
		}
		Scanner sc2 = new Scanner(System.in);
		System.out.println("请输入一个小于" + i + "的数");
		int m = sc2.nextInt();
		sc.close();
		sc2.close();

这样该报错就解决了！

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注：以上文章仅是个人学习过程总结，若有不当之处，望不吝赐教。