如何在BufferedImage中使颜色透明并保存为PNG

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.ImageIO;

public class TransparentPNG {
    public static void main(String[] args) {
        try {
            // 读取原始图像
            BufferedImage originalImage = ImageIO.read(new File("input.png"));

            // 创建一个具有透明度的BufferedImage
            BufferedImage transparentImage = new BufferedImage(originalImage.getWidth(), originalImage.getHeight(), BufferedImage.TYPE_INT_ARGB);

            // 创建一个Graphics2D对象
            Graphics2D g2d = transparentImage.createGraphics();

            // 绘制原始图像
            g2d.drawImage(originalImage, 0, 0, null);

            // 设置颜色为透明
            Color transparentColor = new Color(255, 255, 255, 0);
            g2d.setColor(transparentColor);

            // 绘制透明区域
            g2d.fillRect(0, 0, transparentImage.getWidth(), transparentImage.getHeight());

            // 保存为PNG文件
            ImageIO.write(transparentImage, "png", new File("output.png"));

            // 关闭Graphics2D对象
            g2d.dispose();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}