我想要做的是创建一个while循环，在该循环中运行程序菜单，直到用户输入有效响应。
但是，我创建的扫描仪实例不想打球，并且无论我尝试了什么都会抛出 NoSuchElementExceptions。
import java.util.Scanner;
public class Menu
{
Menu()
{
isValid = false;
uInput = 0;
}
public int mMain()
{
Scanner in2;
do
{
in2 = new Scanner(System.in); //For user input
System.out.println("Please choose from the following options");
System.out.println("1) Enter Employee Data");
System.out.println("2) Look Up Employee Information");
System.out.println("3) Employee Comparison");
System.out.println("4) Quit");
uInput = in2.nextInt(); //This is the line throwing the exception.
if (uInput < 1 || uInput > 4)
{
System.out.println("Your choice was not valid, please choose another option.");
}
else
{
isValid = true;
in2.close();
}
} while (!isValid);
isValid = false; //reset for next time
System.out.println("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"); //Clear screen
return uInput;
}
int uInput; //For user input
String uInput2; //for bug fixing
boolean isValid; //check for valid use input
}
如果需要这里是我的主要方法：
public class prg420_w4_commission_program
{
public static void main(String[] args)
{
//class references
Processing proc = new Processing();
Menu menu = new Menu();
//Set up Variables
int uInput; //For user input
boolean uQuit = false; //set up program loop bool
//Opening message
System.out.println("Welcome to the Employee Data Entry Creation program. Please follow the on-screen prompts.");
System.out.println("");
proc.initEDatabase(); //initialize employee database
while (!uQuit)
{
uInput = menu.mMain(); //call main menu
//Check user input
switch (uInput)
{
case 1:
proc.addEDBEntry(); //add employee entries
break;
case 2:
proc.findEmployee();
break;
case 3:
proc.sortEDBase();
break;
case 4:
uQuit = true;
break;
default:
proc.addEDBEntry();
break;
}
}
System.out.println("Thank you for using the Employee Data Entry Creation program.");
}
}