Java 生成旋螺矩阵

    @Test
    public void virtualMain() {
        int[][] matrix = generateMatrix(9);
        MyArray.printSquareArray(matrix, 2);
    }

    public int[][] generateMatrix(int n) {
        int[][] res = new int[n][n];
        int square = n * n, i = (int) Math.ceil(n / 2.00);
        int row = 0, column = 0;
        int counter = 1;
        int layer = 0;
        while (layer < i) {
            int starter = n - layer * 2;
            for (int j = counter, len = starter + counter - 1; j <= len; j++) {
                res[column][row++] = counter++;
            }
            row--;
            column++;
            for (int j = counter, len = starter + counter - 2; j <= len; j++) {
                res[column++][row] = counter++;
            }
            column--;
            row--;

            for (int j = counter, len = starter + counter - 1; j < len; j++) {
                res[column][row--] = counter++;
            }

            row++;
            column--;

            for (int j = counter, len = starter + counter - 2; j < len; j++) {
                res[column--][row] = counter++;
            }

            row++;
            column++;
            layer++;
        }
        return res;
    }

//辅助打印
    /**
     * format with output
     * @param data two dimension array
     * @param unitLen the maximum value of data unit length
     */
    public static void printSquareArray(int[][] data,int unitLen){
        unitLen+=1;

        for (int i = 0; i < data.length; i++) {
            for (int j = 0,len=data[0].length; j < len; j++) {
                System.out.print(data[i][j]);
                int unit = String.valueOf(data[i][j]).length();
                printSpace(unitLen - unit);
            }
            System.out.println("");
        }
    }

    private static void printSpace(int num){
        while (num-- > 0) System.out.print(" ");
    }