java 动态二维数组文件读写

1. 文件读取

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

public class Dynamic2DArrayFileReader {
    public static void main(String[] args) {
        try {
            File file = new File("input.txt");
            Scanner scanner = new Scanner(file);

            // Read the number of rows and columns
            int rows = scanner.nextInt();
            int cols = scanner.nextInt();

            // Initialize the 2D array
            int[][] array = new int[rows][cols];

            // Read the elements of the array
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < cols; j++) {
                    array[i][j] = scanner.nextInt();
                }
            }

            // Print the array
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < cols; j++) {
                    System.out.print(array[i][j] + " ");
                }
                System.out.println();
            }

            scanner.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

2. 文件写入

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;

public class Dynamic2DArrayFileWriter {
    public static void main(String[] args) {
        int[][] array = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};

        try {
            File file = new File("output.txt");
            PrintWriter writer = new PrintWriter(file);

            // Write the number of rows and columns
            writer.println(array.length);
            writer.println(array[0].length);

            // Write the elements of the array
            for (int i = 0; i < array.length; i++) {
                for (int j = 0; j < array[0].length; j++) {
                    writer.print(array[i][j] + " ");
                }
                writer.println();
            }

            writer.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}