我正在尝试使用servlet和以下代码绘制形状，但图像未显示

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ShapeServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 创建一个BufferedImage对象，宽度为200，高度为200，类型为RGB
        BufferedImage image = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
        
        // 获取Graphics对象，用于绘制形状
        Graphics graphics = image.getGraphics();
        
        // 设置形状的颜色为红色
        graphics.setColor(Color.RED);
        
        // 绘制一个矩形形状，起始点坐标为(50, 50)，宽度为100，高度为100
        graphics.fillRect(50, 50, 100, 100);
        
        // 释放资源
        graphics.dispose();
        
        // 将图像写入输出流
        ImageIO.write(image, "png", response.getOutputStream());
    }
}