用Java写一个程序实现，从键盘输入一个N值（3<=N<=10)，生成N*N矩阵，实现将矩阵最外围元素顺时针旋转并去核，去核后仅保留最外围元素。要求：1.原矩阵中各值（0<=x<100)随机生成。2.测试程序时应能反映矩阵变化，先原矩阵再旋转后的矩阵，再去核后的矩阵，并规范矩阵输出格式。

以下是Java代码实现：

import java.util.Scanner;

public class MatrixRotation {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入矩阵的大小（3<=N<=10）：");
        int n = scanner.nextInt();
        int[][] matrix = new int[n][n];
        int maxNum = n * n - 1;
        int i = 0, j = 0, num = 0;
        while (num <= maxNum) {
            while (j < n && matrix[i][j] == 0) {
                matrix[i][j] = (int) (Math.random() * 100);
                num++;
                j++;
            }
            j--;
            i++;
            while (i < n && matrix[i][j] == 0) {
                matrix[i][j] = (int) (Math.random() * 100);
                num++;
                i++;
            }
            i--;
            j--;
            while (j >= 0 && matrix[i][j] == 0) {
                matrix[i][j] = (int) (Math.random() * 100);
                num++;
                j--;
            }
            j++;
            i--;
            while (i >= 0 && matrix[i][j] == 0) {
                matrix[i][j] = (int) (Math.random() * 100);
                num++;
                i--;
            }
            i++;
            j++;
        }
        System.out.println("原矩阵：");
        printMatrix(matrix);
        int[][] rotatedMatrix = rotateMatrix(matrix);
        System.out.println("旋转后的矩阵：");
        printMatrix(rotatedMatrix);
        int[] outerElements = removeCore(rotatedMatrix);
        System.out.println("去核后的矩阵：");
        printOuterElements(outerElements, n);
    }

    // 顺时针旋转矩阵
    private static int[][] rotateMatrix(int[][] matrix) {
        int n = matrix.length;
        int[][] rotatedMatrix = new int[n][n];
        for (int i = 0; i < n / 2; i++) {
            for (int j = i; j < n - i - 1; j++) {
                int temp = matrix[i][j];
                rotatedMatrix[i][j] = matrix[n - j - 1][i];
                rotatedMatrix[n - j - 1][i] = matrix[n - i - 1][n - j - 1];
                rotatedMatrix[n - i - 1][n - j - 1] = matrix[j][n - i - 1];
                rotatedMatrix[j][n - i - 1] = temp;
            }
        }
        return rotatedMatrix;
    }

    // 去核，返回最外层元素数组
    private static int[] removeCore(int[][] matrix) {
        int n = matrix.length;
        int[] outerElements = new int[2 * (n - 1) + 2 * (n - 2)];
        int index = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (i == 0 || j == 0 || i == n - 1 || j == n - 1) {
                    outerElements[index++] = matrix[i][j];
                }
            }
        }
        return outerElements;
    }

    // 打印矩阵
    private static void printMatrix(int[][] matrix) {
        int n = matrix.length;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                System.out.printf("%3d", matrix[i][j]);
            }
            System.out.println();
        }
    }

    // 打印最外层元素数组
    private static void printOuterElements(int[] outerElements, int n) {
        for (int i = 0; i < n - 1; i++) {
            System.out.printf("%3d", outerElements[i]);
        }
        for (int i = n - 1; i < 2 * n - 2; i++) {
            System.out.printf("%3d", outerElements[i]);
        }
        for (int i = 2 * n - 2; i < 3 * n - 3; i++) {
            System.out.printf("%3d", outerElements[i]);
        }
        for (int i = 3 * n - 3; i < 4 * n - 4; i++) {
            System.out.printf("%3d", outerElements[i]);
        }
        System.out.println();
    }
}

代码中，我们首先根据输入的 `n` 值生成一个随机矩阵，然后对该矩阵进行顺时针旋转和去核操作，并输出矩阵的变化过程和最终结果。其中，旋转矩阵的算法采用了模拟旋转的方式，而去核操作则是通过遍历矩阵的方式来实现的。最后，我们还定义了两个辅助函数 `printMatrix` 和 `printOuterElements`，用于规范输出矩阵和最外层元素数组。