怎么用java 给图片添加水印

如何用java 给图片添加水印
Image src = javax.imageio.ImageIO.read(file); //构造Image对象
float tagsize=400;
int old_w=src.getWidth(null); //得到源图宽
int old_h=src.getHeight(null);
int new_w=0;
int new_h=0; //得到源图长
int tempsize;
float tempdouble;
if(old_w>old_h){
tempdouble=old_w/tagsize;
}else{
tempdouble=old_h/tagsize;
}
new_w=Math.round(old_w/tempdouble);
new_h=Math.round(old_h/tempdouble);//计算新图长宽
BufferedImage tag = new BufferedImag(new_w,new_h,BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(src,0,0,new_w,new_h,null); //绘制缩小后的图
//以上实现图片缩略图
Graphics g=tag.createGraphics();
String s="本图片，版权所有"; //图片中显示的字体
g.setColor(Color.WHITE);
g.setFont(new Font("宋体",Font.PLAIN,12));
Font dd=new Font("宋体",Font.PLAIN,10);
g.drawString(s,new_w-230,new_h-5);
g.dispose();

FileOutputStream newimage=new FileOutputStream(newurl); //输出到文件流
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);
encoder.encode(tag); //近JPEG编码
newimage.close();
pressText("李白",newurl,"font-weight", Font.BOLD,255,70,700, 100);
pressImage("D:\\pic\\11.png",newurl, 0, 0) ;

/** *//**
     * 把图片印刷到图片上
     *  @param pressImg --
     *            水印文件
     * @param targetImg --
     *            目标文件
     * @param x
     *            --x坐标
     * @param y
     *            --y坐标
     */
    public final static void pressImage(String pressImg, String targetImg,
            int x, int y) {
        try {
            //目标文件
            File _file = new File(targetImg);
            Image src = ImageIO.read(_file);
            int wideth = src.getWidth(null);
            int height = src.getHeight(null);
            BufferedImage image = new BufferedImage(wideth, height,
                    BufferedImage.TYPE_INT_RGB);
            Graphics g = image.createGraphics();
            g.drawImage(src, 0, 0, wideth, height, null);

            //水印文件
            File _filebiao = new File(pressImg);
            Image src_biao = ImageIO.read(_filebiao);
            int wideth_biao = src_biao.getWidth(null);
            int height_biao = src_biao.getHeight(null);
            g.drawImage(src_biao, (wideth - wideth_biao) / 2,
                    (height - height_biao) / 2, wideth_biao, height_biao, null);
            //水印文件结束
            g.dispose();
            FileOutputStream out = new FileOutputStream(targetImg);
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
            encoder.encode(image);
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /** *//**
     * 打印文字水印图片
     *
     * @param pressText
     *            --文字
     * @param targetImg --
     *            目标图片
     * @param fontName --
     *            字体名
     * @param fontStyle --
     *            字体样式
     * @param color --
     *            字体颜色
     * @param fontSize --
     *            字体大小
     * @param x --
     *            偏移量
     * @param y
     */

    public static void pressText(String pressText, String targetImg,
            String fontName, int fontStyle, int color, int fontSize, int x,
            int y) {
        try {
            File _file = new File(targetImg);
            Image src = ImageIO.read(_file);
            int wideth = src.getWidth(null);
            int height = src.getHeight(null);
            BufferedImage image = new BufferedImage(wideth, height,
                    BufferedImage.TYPE_INT_RGB);
            Graphics g = image.createGraphics();
            g.drawImage(src, 0, 0, wideth, height, null);
            // String s="www.qhd.com.cn";
            g.setColor(new Color(color,false));
            g.setFont(new Font(fontName, fontStyle, fontSize));

            g.drawString(pressText, wideth - fontSize - x, height - fontSize
                    / 2 - y);
            g.dispose();
            FileOutputStream out = new FileOutputStream(targetImg);
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
            encoder.encode(image);
            out.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }