Java实现图片水印效果

    /**
     * 图片添加水印效果
     * @param filename 图片文件名称
     * @param resultFilename 目标文件名称
     * @throws IOException 
     */
    public void watermarkForImage(String filename,String resultFilename) throws IOException{
        //创建文件对象
        File file = new File(filename);
        //判断文件是否存在
        if (!file.exists()) {
            System.out.println("文件不存在");
            return;
        }
        ImageIcon imageIcon = new ImageIcon(file.getPath());
        BufferedImage bufferedImage = new BufferedImage(
                imageIcon.getIconWidth(), imageIcon.getIconHeight(), BufferedImage.TYPE_INT_BGR);
        Graphics2D graphics2d = (Graphics2D)bufferedImage.getGraphics();
        graphics2d.drawImage(imageIcon.getImage(), 0, 0, null);
        AlphaComposite alphaComposite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER,1f);
        graphics2d.setComposite(alphaComposite);
        //设置颜色
        graphics2d.setColor(Color.WHITE);
        graphics2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        //字体设置
        graphics2d.setFont(new Font("微软雅黑", Font.BOLD, 32));
        //水印文字
        String watermarkText = "水印效果测试";
        //设置水印文字和文字
        graphics2d.drawString(watermarkText, 0, 32);
        graphics2d.dispose();
        File resultFile = new File(resultFilename);
        ImageIO.write(bufferedImage, "png", resultFile);
        System.out.println("success!");
    }