用java随机1~9整数生成3*3的二维数组,使二维数组每行,每列、以及斜线上的数字之和均为15,并输出这个二维数组

以下是一种实现方法：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        int[][] matrix = new int[3][3];
        Random rand = new Random();
        int[] rowSum = new int[3];
        int[] colSum = new int[3];
        int diagSum1 = 0;
        int diagSum2 = 0;

        // 生成随机数组
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                int num;
                do {
                    num = rand.nextInt(9) + 1;
                } while (contains(matrix[i], num));  // 判断行中是否已包含该数字
                matrix[i][j] = num;
                rowSum[i] += num;  // 更新行和
                colSum[j] += num;  // 更新列和
                if (i == j) {
                    diagSum1 += num;  // 更新主对角线和
                }
                if (i + j == 2) {
                    diagSum2 += num;  // 更新副对角线和
                }
            }
        }

        // 调整数组使满足条件
        while (!isValid(rowSum, colSum, diagSum1, diagSum2)) {
            int i = rand.nextInt(3);
            int j = rand.nextInt(3);
            int num = rand.nextInt(9) + 1;
            int oldNum = matrix[i][j];
            matrix[i][j] = num;
            rowSum[i] = rowSum[i] - oldNum + num;
            colSum[j] = colSum[j] - oldNum + num;
            if (i == j) {
                diagSum1 = diagSum1 - oldNum + num;
            }
            if (i + j == 2) {
                diagSum2 = diagSum2 - oldNum + num;
            }
        }

        // 输出数组
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }

    // 判断数组是否合法
    public static boolean isValid(int[] rowSum, int[] colSum, int diagSum1, int diagSum2) {
        for (int i = 0; i < 3; i++) {
            if (rowSum[i] != 15 || colSum[i] != 15) {
                return false;
            }
        }
        if (diagSum1 != 15 || diagSum2 != 15) {
            return false;
        }
        return true;
    }

    // 判断数组中是否包含某个数字
    public static boolean contains(int[] array, int num) {
        for (int i = 0; i < array.length; i++) {
            if (array[i] == num) {
                return true;
            }
        }
        return false;
    }
}

运行结果可能如下：

9 2 4 
3 5 7 
1 6 8