Java输出一个空心菱形

以下是Java代码，可以输出一个空心菱形：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入菱形的大小：");
        int n = scanner.nextInt();

        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n - i; j++) {
                System.out.print(" ");
            }

            for (int j = 1; j <= 2 * i - 1; j++) {
                if (j == 1 || j == 2 * i - 1) {
                    System.out.print("*");
                } else {
                    System.out.print(" ");
                }
            }

            System.out.println();
        }

        for (int i = n - 1; i >= 1; i--) {
            for (int j = 1; j <= n - i; j++) {
                System.out.print(" ");
            }

            for (int j = 1; j <= 2 * i - 1; j++) {
                if (j == 1 || j == 2 * i - 1) {
                    System.out.print("*");
                } else {
                    System.out.print(" ");
                }
            }

            System.out.println();
        }
    }
}

输出示例：

请输入菱形的大小：5
    *
   * *
  *   *
 *     *
*       *
 *     *
  *   *
   * *
    *