用java代码for循环画三角形，并且保存到自定义的文件夹里

好的，以下是用 Java 代码 for 循环画三角形并保存到自定义文件夹的示例代码：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class TriangleDrawer {
    public static void main(String[] args) {
        int width = 300;
        int height = 300;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, width, height);
        g.setColor(Color.BLACK);
        int x1 = 50, y1 = 50;
        int x2 = 150, y2 = 250;
        int x3 = 250, y3 = 50;
        g.drawLine(x1, y1, x2, y2);
        g.drawLine(x2, y2, x3, y3);
        g.drawLine(x3, y3, x1, y1);
        g.dispose();
        try {
            File outputfile = new File("custom_folder/triangle.png");
            outputfile.getParentFile().mkdirs();
            ImageIO.write(image, "png", outputfile);
            System.out.println("Triangle saved to " + outputfile.getAbsolutePath());
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

这段代码会在自定义的文件夹 "custom_folder" 中生成一个名为 "triangle.png" 的文件，里面是一个画好的三角形。