java给图片添加水印

以下是Java给图片添加水印的示例代码：

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class AddWatermark {
    public static void main(String[] args) {
        try {
            // 读取图片
            BufferedImage originalImage = ImageIO.read(new File("original.jpg"));

            // 创建一个带有透明度的图片
            BufferedImage watermarkedImage = new BufferedImage(originalImage.getWidth(), originalImage.getHeight(), BufferedImage.TYPE_INT_ARGB);

            // 获取Graphics2D对象
            Graphics2D g2d = (Graphics2D) watermarkedImage.getGraphics();

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

            // 设置水印透明度
            AlphaComposite alphaComposite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f);
            g2d.setComposite(alphaComposite);

            // 设置水印字体
            Font font = new Font("Arial", Font.BOLD, 36);
            g2d.setFont(font);

            // 设置水印颜色
            g2d.setColor(Color.BLACK);

            // 设置抗锯齿
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

            // 绘制水印
            String watermark = "© My Watermark";
            int x = watermarkedImage.getWidth() - g2d.getFontMetrics().stringWidth(watermark) - 20;
            int y = watermarkedImage.getHeight() - 20;
            g2d.drawString(watermark, x, y);

            // 保存文件
            ImageIO.write(watermarkedImage, "png", new File("watermarked.png"));

            // 释放资源
            g2d.dispose();

            System.out.println("Watermark added successfully!");
        } catch (IOException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

以上代码使用了Java的ImageIO和Graphics2D类来读取、处理和保存图片。它首先读取原始图片，然后创建一个带有透明度的图片，并在其上绘制水印。在绘制水印时，它使用了透明度、字体、颜色和抗锯齿等设置。最后，它将水印添加到原始图片中，并保存为新的文件。