扫描文件时出现 java.util.NoSuchElementException

Question

我正在读取文件并将所有内容保存到其中。整个程序运行良好，但我没有阅读文件的最后一行，当我尝试这样做时，事情变得很奇怪，文件的最后一行是“END_OF_FILE”。我尝试将它保存为一个字符串，当我收到错误消息时它不起作用，但现在我从我的代码中取出了所有这些并且它没有完全运行程序，它输出的最后一件事是工作是的是我在 main 中的最后一个 for 循环。

这是我的代码:

import java.io.*;

import java.util.Scanner;
public class hurry2 {

    public static void main (String [] args) throws IOException
    {
        File candidates = new File("cipcs115.txt");
        Scanner scan = new Scanner(candidates);
        Scanner user = new Scanner(System.in);
        String state = scan.next();
        int numOfCan = scan.nextInt();
        String what = scan.nextLine();

        String stateWi ;
        String stateAl ;
        String stateDe ;

        int numOfCanWi ;
        int numOfCanAl ;
        int numOfCanDe ;

        Candidate [] candiIl ;
        Candidate [] candiWi;
        Candidate [] candiAl ;
        Candidate [] candiDe;
        hurry2 cill = new hurry2();   

        candiIl = new Candidate[numOfCan];
        for ( int i=0; i<numOfCan; i++)
        {
            String three = scan.next();
            String four = scan.next();
            String five = scan.next();
            int six = scan.nextInt();
            double seven = scan.nextDouble();
            String eight = scan.nextLine();

            Candidate night  = new Candidate (three,four,five,six,seven,eight);
            candiIl [i] = night ;
            System.out.println(night.getName() + "  " + night.getMotto());
        }

        stateWi = scan.next();
        numOfCanWi = scan.nextInt();

        candiWi = new Candidate[numOfCanWi];
        for ( int i=0; i<numOfCanWi; i++)
        {
            String three = scan.next();
            String four = scan.next();
            String five = scan.next();
            int six = scan.nextInt();
            double seven = scan.nextDouble();
            String eight = scan.nextLine();

            Candidate night  = new Candidate (three,four,five,six,seven,eight);
            candiWi [i] = night ;
            System.out.println(night.getName() + "  " + night.getMotto());
        }

        stateAl = scan.next();
        numOfCanAl = scan.nextInt();

        candiAl = new Candidate[numOfCanAl];
        for ( int i=0; i<numOfCanAl; i++)
        {
            String three = scan.next();
            String four = scan.next();
            String five = scan.next();
            int six = scan.nextInt();
            double seven = scan.nextDouble();
            String eight = scan.nextLine();

            Candidate night  = new Candidate (three,four,five,six,seven,eight);
            candiAl [i] = night ;
            System.out.println(night.getName() + "  " + night.getMotto());
        }

        stateDe = scan.next();
        numOfCanDe = scan.nextInt();

        candiDe = new Candidate[numOfCanDe];
        for ( int i=0; i<numOfCanAl; i++)
        {
            String three = scan.next();
            String four = scan.next();
            String five = scan.next();
            int six = scan.nextInt();
            double seven = scan.nextDouble();
            String eight = scan.nextLine();

            Candidate night  = new Candidate (three,four,five,six,seven,eight);
            candiDe [i] = night ;
            System.out.println(night.getName() + "  " + night.getMotto());
            System.out.println("yes");
        }

        System.out.println(" what would you like to do? >");
        String option = user.next();
        switch (option)
        {
            case "m":
            case "M":
                cill.menu(candiIl);
                break;
        }
        scan.close();    
    }

    public static void menu(Candidate [] rod)
    { 
        hurry2 cill1 = new hurry2();
        Scanner menus = new Scanner(System.in);
        System.out.print( "What would you like to do next >");
        String option1 = menus.next() ;
        switch (option1)
        { 
            case "l" :
            case "L" :
                cill1.listall(rod);
                break ;
        }
        return ;
    }
    public static void listall(Candidate [] yes)
    {
        int numOfCan = 3;
        for (int s =0; s<numOfCan;s++)
            System.out.println(yes[s].getName() + yes[s].getParty() + yes[s].getMotto());
        return ;
    }
}

这是我的整个错误消息，这个程序再次输出直到单词 yes 的所有内容，我将其包含在数组 candiDe 的最后一个 for 循环中。在此先感谢您的帮助。

Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:907)
    at java.util.Scanner.next(Scanner.java:1416)
    at hurry2.main(hurry2.java:91)

Answer 1

您似乎正在尝试多次调用 scan.next() 方法，但未检查 scan.hasNext() 方法。

在调用 next() 方法之前尝试使用 scan.hasNext()。