从JAVA中第一行指定了矩阵大小的文件中读取矩阵

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public class MatrixReader {
    public static void main(String[] args) {
        String filePath = "matrix.txt"; // 文件路径和名称

        try {
            File file = new File(filePath);
            FileReader fileReader = new FileReader(file);
            BufferedReader bufferedReader = new BufferedReader(fileReader);

            String line;
            int rowCount = 0;
            int colCount = 0;
            int[][] matrix = null;

            while ((line = bufferedReader.readLine()) != null) {
                if (rowCount == 0) {
                    // 解析第一行，获取矩阵的行列数
                    String[] size = line.split(" ");
                    rowCount = Integer.parseInt(size[0]);
                    colCount = Integer.parseInt(size[1]);
                    matrix = new int[rowCount][colCount];
                } else {
                    // 解析矩阵元素值并存储到二维数组中
                    String[] elements = line.split(" ");
                    for (int i = 0; i < colCount; i++) {
                        matrix[rowCount - 1][i] = Integer.parseInt(elements[i]);
                    }
                    rowCount--;
                }
            }

            // 输出读取到的矩阵
            for (int i = 0; i < matrix.length; i++) {
                for (int j = 0; j < matrix[i].length; j++) {
                    System.out.print(matrix[i][j] + " ");
                }
                System.out.println();
            }

            bufferedReader.close();
            fileReader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}