I / O滥用引起的线程“ main”中的异常java.util.NoSuchElementException？

Question

我写了这个程序，作为飞机的座位表。我在Java中使用I / O相当陌生，并且遇到了这些运行时错误：

Exception in thread "main" java.util.NoSuchElementException

at java.util.Scanner.throwFor(Scanner.java: 862)

at java.util.Scanner.next(Scanner.java: 1371)

at AirplaneSeatProgram.main(AirplaneSeatProgram.java:27)

我认为这与过早关闭I / O有关（特别是在代码的第27行？），但我不确定。有人可以帮我吗？我将在下面发布代码。

import java.util.*; //imports all java.util classes
import java.io.*; //importa all java.io classes

public class AirplaneSeatProgram{

   //main method
   public static void main(String[] args){

      //constructs a Scanner object to accept input
      Scanner myScanner=new Scanner(System.in);

      //creates an input stream object linked to the file
      Scanner inputStream;
      char[][] mySeatMap=new char[9][8];
      //tries to access the file
      try{
         inputStream=new Scanner(new FileInputStream("seatsmap.txt"));
         for (int i=0; i<mySeatMap.length; i++){
            for (int j=0; j<mySeatMap[i].length; j++){
               //mySeatMap[i][j]=inputStream.next().charAt(0);
               mySeatMap[i][j]=inputStream.next().charAt(0);
            }
         }
      }
      //if the file doesn't exist, create a file
      catch (FileNotFoundException e) {
         for (int i=0; i<mySeatMap.length; i++){
            for (int j=0; j<mySeatMap[i].length; j++){
               mySeatMap[i][j]='.';
            }
         }
      } 

      //displays a menu for the user to select an operation until the user selects "Exit"
      int myChoice=0;
      while (myChoice!=3){
         System.out.println();
         System.out.println("Please select an operation:");
         System.out.println("1: Reserve a seat");
         System.out.println("2: Free a seat");
         System.out.println("3: Exit");
         myChoice=myScanner.nextInt();
         display(mySeatMap);

         //if the user selects 1, call the reserve() method
         if (myChoice==1){
            //checks to see if the input is valid
            String regex="[0-9][a-hA-H]";
            System.out.println("Enter a seat number (ex. 4C):");
            String seatNumber=myScanner.next();
            boolean isValid=isValid(seatNumber, regex);
            int row=row(seatNumber);
            int column=column(seatNumber);
            System.out.println("row="+row);
            System.out.println("column="+column);
            //if the input is valid and the seat is available, reserve the seat
            if (isValid){
               if (mySeatMap[row][column]=='.'){
                  reserve(mySeatMap, row, column);
               }
               else{
                  System.out.println("Seat already taken.");
               }
            }
            //otherwise throw an error
            else{
               InvalidSeatException e=new InvalidSeatException();
               e.toString();
            }
         }

         //if the user selects 2, call the free() method
         if (myChoice==2){
            //checks to see if the input is valid
            String regex="[0-9][a-hA-H]";
            System.out.println("Enter a seat number (ex. 4C):");
            String seatNumber=myScanner.next();
            boolean isValid=isValid(seatNumber, regex);
            int row=row(seatNumber);
            int column=column(seatNumber);
            //if the input is valid and the seat is unavailable, free the seat
            if (isValid){
               if (mySeatMap[row][column]!='.'){
                  free(mySeatMap, row, column);
               }
               else{
                  System.out.println("Seat already free.");
               }
            }
            //otherwise throw an error
            else{
               InvalidSeatException e=new InvalidSeatException();
               e.toString();
            }
         }

         if (myChoice==3){
            //creates an output stream object linked to a file
            PrintWriter outputStream;
            try{
               outputStream=new PrintWriter(new FileOutputStream("seatsmap.txt"));
               for (int i=0; i<mySeatMap.length; i++){
                  for (int j=0; j<mySeatMap[i].length; j++){
                     outputStream.print(mySeatMap[i][j]+" ");
                  }
                  outputStream.println();
               }
            }
            catch (FileNotFoundException e) {
               System.out.println("Cannot create file because the file cannot be found.");
               System.exit(0);
            }
         }

         //if the user enters an invalid number from the menu, tell them to try again
         if (myChoice>3){
            System.out.println();
            System.out.println("Invalid selection. Please try again.");
         }
      }
   }

    //method to reserve a seat
    public static void reserve(char[][] a, int r, int c){
       a[r][c]='x';
       System.out.println("Successfully reserved your seat.");
    }

    //method to free a seat
    public static void free(char[][] a, int r, int c){
       a[r][c]='.';
       System.out.println("Successfully freed the seat.");
    }

   //method to determine if seat is valid
   public static boolean isValid(String a, String b){
      if (!a.matches(b)){
         return false;
      }
      else{
         return true;
      }
   }

   //method to return the row
   public static int row(String a){
      char b=a.charAt(0);
      int c=Character.getNumericValue(b);  
      return c;
   }

   //method to return the column
   public static int column(String a){
      char b=a.charAt(0);
      int c=(Character.getNumericValue(b))-2;
      if(c>10){
         int d=(Character.getNumericValue(b))-2;
         return d;
      }
      else{
         return c;
      }
   }

   //method to display the seating chart
   public static void display(char[][] a){
      System.out.println();
      System.out.println("   A  B  C  D  E  F  G  H");
      for (int i=0; i<9; i++){
         System.out.print(i+1);
         for (int j=0; j<8; j++){
            System.out.print("  "+a[i][j]);
         }
         System.out.println();
      }
   }

}