如何修复引发的“NoSuChelementException”

Question

我创建了一个用于解决运动方程问题的交互式类（在用户输入循环中的另一个类中访问：mathiverse），它工作得很好，但是在给出答案后，它抛出一个NoSuchelementException。

while(!(input.equals("exit")))
{
    if(input.equals("help"))
    {
        System.out.println("~ Commands ~");
        System.out.println("help - brings up a list of 
        commands(what you're reading)");
        System.out.println("kinematic - solves a kinematic 
        equations problem; requires input of known and unknown 
        variables");
        System.out.println("exit - closes the program");
        System.out.println("~~~~~~~~~~~~");
    }

    //user decides to explore kinematic options
    if(input.equals("kinematic"))
    {
        Kinematic calc = new Kinematic();

        System.out.println(calc.answer());
    }

    input = scan.nextLine();
}

public Kinematic()
{
    Scanner scanMath = new Scanner(System.in);

    System.out.println("If you are solving for the variable, enter \"?\", 
    if the variable is not given, enter a space.");
    System.out.println("Enter the acceleration: ");
    acc = scanMath.nextLine();

    System.out.println("Enter the displacement: ");
    disp = scanMath.nextLine();

    System.out.println("Enter the initial velocity: ");
    init = scanMath.nextLine();

    System.out.println("Enter the final velocity: ");
    fin = scanMath.nextLine();

    System.out.println("Enter the time: ");
    time = scanMath.nextLine();

    scanMath.close();
}

线程“main”java.util.NoSuChelementException：在mathiverse.main(mathiverse.java:53)的java.base/java.util.scanner.nextline（scanner.java:1651)上找不到行

Answer 1

当从运动学中关闭扫描仪时，您关闭了系统。在流中也是如此。在主方法和运动学中使用相同的扫描仪。

看一下：java.util.NoSuChelementException-Scanner读取用户输入