JAVA给图片加水印，可设置透明度

/**
??? ?* 图片加水印，可设置透明度,默认水印图片放在右下角
??? ?* @param iconFile 水印文件
??? ?* @param srcImgFile 源文件
??? ?* @param alpha 透明度 0-1
??? ?* @return 生成的图片字节数组
??? ?*/
??? public static byte[] markImageByIcon(File iconFile, File srcImgFile,float alpha) {
??? ???
??? ??? byte[] imgBytes = null;

??? ??? try {
??? ??? ??? Image srcImg = ImageIO.read(srcImgFile);
??? ??? ??? int width = srcImg.getWidth(null);
??? ??? ??? int height = srcImg.getHeight(null);
??? ??? ??? BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
??? ??? ??? Graphics2D g = buffImg.createGraphics();
??? ??? ??? g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
??? ??? ??? g.drawImage(srcImg.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);
??? ??? ??? Image mark_img = ImageIO.read(iconFile);
??? ??? ??? int mark_width = mark_img.getWidth(null);
??? ??? ??? int mark_height = mark_img.getHeight(null);
??? ??? ??? g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
??? ??? ??? g.drawImage(mark_img, width - mark_width,? height - mark_height, null);
??? ??? ??? g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));
??? ??? ??? g.dispose();
??? ??? ??? ByteArrayOutputStream out = new ByteArrayOutputStream();
??? ??? ??? ImageIO.write(buffImg, "JPG", out);
??? ??? ??? imgBytes = out.toByteArray();
??? ??? } catch (Exception e) {
??? ??? ??? e.printStackTrace();
??? ??? }
??? ??? return imgBytes;
??? }