在java.util.Scanner.throwFor（未知源）错误

在java.util.Scanner.throwFor（未知源）错误

打电话时

next

，应检查扫描仪是否有一个。

 if(scan.hasNext()) scan.next();

根据Scanner＃next的
Java文档

NoSuchElementException如果没有更多标记可用

您可以如下更改方法

private static int posNum(Scanner scan) {    int input = 0;    boolean error = false;    if (scan.hasNext()) {        if (scan.hasNextInt()) { input = scan.nextInt(); error = input <= 0;        } else { scan.next(); error = true;        }    }    while (error) {        System.out.print("Invalid input. Please reenter: ");        if (scan.hasNextInt()) { input = scan.nextInt(); error = input <= 0;        } else { if (scan.hasNext())     scan.next(); error = true;        }    }    return input;}

然后像下面这样称呼它

    Scanner scan = new Scanner(System.in);    int i = posNum(scan);    System.out.println(i);    int j = posNum(scan);    System.out.println(j);