How to write code in Java to print a diamond shape?.

Here is a Java code example for printing a diamond shape:

import java.util.Scanner;

public class DiamondPattern {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入菱形的行数：");
        int rows = scanner.nextInt();

        int spaces = rows - 1;
        int stars = 1;

        // 打印上半部分
        for (int i = 1; i <= rows; i++) {
            for (int j = 1; j <= spaces; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= stars; j++) {
                System.out.print("*");
            }
            System.out.println();
            spaces--;
            stars += 2;
        }

        // 打印下半部分
        spaces = 1;
        stars = rows * 2 - 3;
        for (int i = 1; i <= rows - 1; i++) {
            for (int j = 1; j <= spaces; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= stars; j++) {
                System.out.print("*");
            }
            System.out.println();
            spaces++;
            stars -= 2;
        }
    }
}

After running the program, you will be prompted to enter the number of rows for the diamond. Once you input the number, the corresponding diamond pattern will be printed.