怎么用java输出杨辉三角

下面是一个用Java输出杨辉三角的示例代码：

import java.util.*;

public class YangHuiTriangle {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入要输出的行数：");
        int numRows = sc.nextInt();
        
        List<List<Integer>> triangle = generate(numRows);
        for (List<Integer> row : triangle) {
            for (int num : row) {
                System.out.print(num + " ");
            }
            System.out.println();
        }
    }
    
    public static List<List<Integer>> generate(int numRows) {
        List<List<Integer>> triangle = new ArrayList<>();
        
        if (numRows == 0) {
            return triangle;
        }
        
        List<Integer> firstRow = new ArrayList<>();
        firstRow.add(1);
        triangle.add(firstRow);
        
        for (int i = 1; i < numRows; i++) {
            List<Integer> prevRow = triangle.get(i - 1);
            List<Integer> currRow = new ArrayList<>();
            
            currRow.add(1);
            for (int j = 1; j < i; j++) {
                currRow.add(prevRow.get(j - 1) + prevRow.get(j));
            }
            currRow.add(1);
            
            triangle.add(currRow);
        }
        
        return triangle;
    }
}

运行这段代码后，输入要输出的行数，程序将会输出相应行数的杨辉三角。