public class TextWaterMark {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        File file = new File("D://big59000.jpg");
        textmark(file,"HELLO WORLD");
    }

    /**
     * @param file
     *            图片文件对象
     * @param text
     *            添加的水印文字
     */
    public static void textmark(File file, String text) {
        try {
            Image image = ImageIO.read(file);

            BufferedImage bufferImage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_RGB);// 1.创建图片缓存对象

            Graphics2D g = bufferImage.createGraphics(); // 2. 创建Java绘图工具对象
            
            g.drawImage(image, 0, 0, image.getWidth(null), image.getHeight(null), null);//3.将原图通过绘图工具画到图片缓存对象中
            
            g.setFont(new Font("微软雅黑",Font.BOLD,30));
            g.setColor(Color.GREEN);//设置水印文字的 字体和颜色
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.3f));
            
            g.drawString(text, 200, 50);//4.将文字添加到缓存图片对象中
            g.dispose();
            
            OutputStream os = new FileOutputStream("D://waterText.jpg");
            ImageIO.write(bufferImage, "JPG", os);//通过图片编码工具，将缓存图片保存到本地
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}