Question

我目前正在从文本文件中的值创建二维数组。例如： 12 23 2342 45 12 6 23 45 54 12 67 2 3 4 5

应该放入一个看似如下的2D数组：

12 23 2342 45 12 6 23 45 0 0 0 0 54 12 0 0 0 0 67 2 3 4 5 0

目前，这是输出：

PROBLEM
null
java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:862)
    at java.util.Scanner.next(Scanner.java:1485)
    at java.util.Scanner.nextInt(Scanner.java:2117)
    at java.util.Scanner.nextInt(Scanner.java:2076)
    at com.company.Class2.readFile(Class2.java:55)
    at com.company.Main.main(Main.java:13)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

这是我的主要课程：

package com.company;
import java.io.*;
import java.util.Arrays;

public class Main {

    public static void main(String[] args) throws IOException {
//Creates new class2 object
            Class2 o = new Class2();
//Creates new file object
            File file = new File("src/com/company/new.txt");
//Takes in file object as parameter
            int[][] array = o.readFile(file);
//prints as an array
            System.out.println(Arrays.toString(array));

    }
}

这是我的另一课：

package com.company;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;

public class Class2 {

    public int[][] readFile(File file) {

        try {

            Scanner scn = new Scanner(file);
            Scanner scn2 = new Scanner(file);

            //set initial count (of rows) to zero
            int maxrows = 0;

            //sets initial count (of columns) to zero
            int maxcolumns = 0;

            // goes through file and counts number of rows to set array parameters
            while (scn.hasNextLine()) {
                maxrows++;
                scn.nextLine();
            }
            //counts number of columns to set array parameters
            BufferedReader lineReader = new BufferedReader(new FileReader(file));
            String line;
            while ((line = lineReader.readLine()) != null) {
                maxcolumns++;
                if (!scn2.hasNext()) {
                    break;
                }
                int count = 0;
                for (int i = 0; i < line.length(); i++) {
                    if (String.valueOf(line.charAt(i)).equals(" ")) {
                        //checks if there is white space
                    } else {
                        count++;
                    }
                }
                }
                // create array of counted size
                int[][] array = new int[maxrows][maxcolumns];

                //new scanner to reset
                Scanner scan1 = new Scanner(file);

                //places integer one by one into array
                for (int row = 0; row < maxrows; row++)
                    for (int column = 0; column < maxcolumns; column++)
                        array[row][column] = scan1.nextInt();
                return array;

        }
        // general exception
        catch (Exception e) {
            System.out.println("PROBLEM");
            e.printStackTrace();
            //returns null array
            return null;

        }




    }
}

Answer 1

看起来像txt文件的问题包含的元素少于您正在阅读的元素。您应该使用以下值填充文本。 12 23 2342 45 12 6 23 45 0 0 0 0 54 12 0 0 0 0 67 2 3 4 5 0

否则你应该知道它何时跳过nextInt（）。

Answer 2

您正在计算maxcolumns错误。最大列与最大行相同。你做了正确的空格检查。但您没有使用从count获得的任何信息。试试这个

while (scn.hasNextLine()) 
{
   maxrows++;
   scn.nextLine();
}

int[][]  arr = new int[maxrows][];   
String[] str_arr = new String[];
int row = 0;
BufferedReader lineReader = new BufferedReader(new FileReader(file));
String line;

while ((line = lineReader.readLine()) != null) 
{
  row++;
  if (!scn2.hasNext()) 
     break;

 str_arr = line.split(" ")
 maxcolumns = str_arr.length;
 for(int i = row - 1; i < row; i++)
 {
    for (int j = 0; j < maxcolumns; j++)
       arr[i][j] = Integer.parseInt(str_arr[j]);
 }
}

扫描程序的Java 2D阵列问题

2 个答案: