java - 如何用文本文件中的字符填充二维字符数组

Question

我需要从文本文件中获取字符，并将它们按行主序存储在 20 x 45 的 2D 字符数组中。然后，我需要打印出存储的字符列主序。这需要适用于任何大小的文本文件。这段代码是我所得到的，但我还无法将其打印出来。

package myfirstjavaproject;

import java.io.*;
import java.util.Scanner;

public class temp {
    public static void main(String[] args)throws Exception{
        File file = new File ("test.txt");
        BufferedReader br = new BufferedReader(new FileReader(file)); 
        String st = br.readLine();  


        int row = 20, column = 45;
        int offset = 0;
        char[][] array = new char [row][column];
        for (int i = 0; i < row; i++) {
            for(int j = 0; j < column; j++) {
                array[i][j] = st.charAt(offset++);
                System.out.print(array[i][j]);
            }
            System.out.println();
        }

    }

}

此代码将其打印出来，然后我收到一条错误消息。

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 55
    at java.lang.String.charAt(Unknown Source)
    at myfirstjavaproject.temp.main(temp.java:18)

Answer 1

/* 我认为您正在尝试以下操作:您可能想使用 stringbuilder 或 stringbuffer 而不是 String */

  public static void main(String[] args)throws Exception{
        File file = new File ("test.txt");
        BufferedReader br = new BufferedReader(new FileReader(file)); 
        String st = br.readLine();  
        String s = null;
        while(br.read()!=-1)
        {
             s=s+br.readLine();
        }

        int row = 20, column = 45;
        int offset = 0;
        char[][] array = new char [row][column];
        for (int i = 0; i < row; i++) {
            for(int j = 0; j < column; j++) {
                array[i][j] = s.charAt(offset++);
                System.out.print(array[i][j]);
            }
            System.out.println();
        }

    }