如何在不使用hasNextInt（）Java的情况下从文本文件读取整数

Question

So I'm new to programming and we have to do this lab where we read from a text file that has only one line with numbers. We then have to put those integers into an array. I know how to read the numbers when they are in separate lines but not when they are in one line. I also know how to put numbers into an array, so I don't need help with that.

The only methods we are allowed to use are:

• hasMoreTokens()
• hasMoreLines()
• readDouble()
• readInt()
• readLine()
• readToken()

Is there a way to do such while using only these methods?

Here is the code:

import chn.util.FileInput;
import chn.util.FileOutput;

public class Compact {
    public Compact (FileInput inFile, FileOutput outFile){
        int[] compactArray = new int [21];
        int numZeroes = 0;
        int num;
        int length = compactArray.length;

    for (int i = 0; i < length; i++) { //making the array for the integers in the list
        compactArray[i] = 0;
    }

    while (inFile.hasMoreLines()) {
        num = 0;
        num = inFile.readInt(); //reads the integers per line
        compactArray[num]++;
    }

    for(int i = 0; i < length; i++) {
        if(compactArray[i] == 0) {
            length--;

            for(int j = i; j < length; j++) {
                compactArray[j] = compactArray[j+1];
            }
            i--; // Decrement i to check the value that was shifted
        } else { 
            numZeroes++;
        }
    }

    // now print the array without 0
    for(int i = 0; i < numZeroes; i++) {
        outFile.print(" " + compactArray[i]);
    }

    outFile.close();
}

For some reason it's simply returning a string of zeroes. I was thinking it may have to do with the way I read the code.

Answer 1

Input: numbers_line.txt which has one line: 1 8 3 43 4 56

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.List; 

public class ReadIntFromFile {

     public static void main(String []args){
        String fileName = "numbers_line.txt";
        List<String> numbersArrayList = new ArrayList<String>();

        try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
            String line;
            while ((line = br.readLine()) != null) {
                numbersArrayList = Arrays.asList(line.split(" "));
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
        String[] numbersStringArray = new String[numbersArrayList.size()];
        numbersStringArray = numbersArrayList.toArray(numbersStringArray);
        int[] numbersIntArray = new int[numbersStringArray.length];
        for(int i = 0;i < numbersStringArray.length;i++) {
            numbersIntArray[i] = Integer.parseInt(numbersStringArray[i]);
        }

        for(int x : numbersIntArray)
             System.out.println(x);
     }
}

Output:

1
8
3
43
4
56