java - 将文件读入数组返回错误的元素

Question

我正在尝试从用户那里获取输入，然后如果它与现有文件之一匹配，则读取该文件并将单词、字母或数字放入一个数组中。 “单词”和“字母”文件似乎工作正常，但“数字”给我带来了问题。它找到文件，读取它，将它放入一个数组中，并给出数字的总和；然而，数组的输出是每隔一个数字，而不是所有数字，就像它应该做的那样。

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class fileIO
{
    public static void main (String[] args) throws FileNotFoundException
    {
        String filename;
        System.out.println("Please enter name of file (alphabet,words,numbers): ");
        Scanner input = new Scanner(System.in);
        filename = input.nextLine();


        if(filename.equals("numbers"))
        {
            int sum = 0;
            Scanner reader = new Scanner(new File("/home/ninjew/workspace/FileIO/src/" + filename + ".txt"));
            ArrayList<Integer> arr = new ArrayList<Integer>();
            while(reader.hasNext())
            {
                arr.add(reader.nextInt());
                sum = sum + reader.nextInt();
            }
            System.out.println(arr);
            System.out.println("The summation is: " + sum);
            reader.close();
        }

        else if(filename.equals("words") || filename.equals("alphabet"))
        {
            Scanner reader = new Scanner(new File("/home/ninjew/workspace/FileIO/src/" + filename + ".txt"));
            // This is for words and letters within the file. Print words and letters.
            ArrayList<String> arr = new ArrayList<String>();

            while(reader.hasNext())
            {
                String line = reader.next();

                Scanner scanner = new Scanner(line);
                scanner.useDelimiter(",");
                while(scanner.hasNext()){
                    arr.add(scanner.next());
                }
                scanner.close();
            }
            System.out.println(arr);
            reader.close();

        }
    }
}

Answer 1

在 if(filename.equals("numbers")) 中，您正在对该 block 中的文件进行两次读取，这就是它跳过数字的原因

        while(reader.hasNext())
        {
            arr.add(reader.nextInt());
            sum = sum + reader.nextInt();
        }

应该是

        while(reader.hasNext())
        {
            int val = reader.nextInt();
            arr.add(val);
            sum = sum + val;
        }