Question

我不确定为什么收到以下消息？：

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)
    at assessed_practical_2.PossibleQuestionSolution.main(PossibleQuestionSolution.java:24)

以下是我的主要方法代码：

    package assessed_practical_2;

    //Importing Resources (Random)
    import java.util.Random;
    //Importing Resources (Scanner)
    import java.util.Scanner;

    public class PossibleQuestionSolution {

        public static void main(String[] args) {

            // Setting up Scanner for User Input
            Scanner scanner = new Scanner(System.in);

            // var declaration
            int userChoice;

        do{ 
            // Invoke displaymenu
            displayMenu();

            // Get user Input for the menu
            System.out.println("Please enter choice from menu...");
            userChoice = scanner.nextInt();

            // Switch statement to decide which method to invoke dependent upon user input

            switch (userChoice) {

            case 1:
                sayUserName();
                break;
            case 2:
                sayUserNameLoop();
                break;
            case 3:
                generateRandomNumbers();
                break;
            case 4:
                triangleArea();
                break;
            case 5:
                System.out.println("Quitting Program");
                break;
            default:
                System.out.println("Sorry didnt recognise Input");
            }// Switch Statement end

        }while (userChoice!=5);

        System.out.println("Goodbye...");

            scanner.close();
        }// end of main method

非常感谢您提供任何帮助，我认为参考扫描仪的nextint行有问题，但我无法修复它！

Answer 1

我更改了以下内容，似乎允许我的程序运行：

public class PossibleQuestionSolution {

// Setting up Scanner for User Input
public static Scanner scanner = new Scanner(System.in);

public static void main(String[] args) {

    // var declaration
    int userChoice;

do{ 
    // Invoke displaymenu
    displayMenu();

    // Get user Input for the menu
    System.out.println("Please enter choice from menu...");
    userChoice = scanner.nextInt();

    // Switch statement to decide which method to invoke dependent upon user input

    switch (userChoice) {

    case 1:
        sayUserName();
        break;
    case 2:
        sayUserNameLoop();
        break;
    case 3:
        generateRandomNumbers();
        break;
    case 4:
        triangleArea();
        break;
    case 5:
        System.out.println("Quitting Program");
        break;
    default:
        System.out.println("Sorry didnt recognise Input");
    }// Switch Statement end

}while (userChoice!=5);

System.out.println("Goodbye...");


}// end of main method

基本上我所做的就是将扫描程序更改为所有方法都可以使用的公共资源，这似乎解决了问题并且不再获得错误异常。

错误消息：没有这样的元素异常？

1 个答案: