複製圖像打水印

        String src = "img.jpg"; // 源文件
        String dec = "img_1.jpg";// 目標文件

        /*
         * 1. 讀取源文件爲圖像文件
         * 2. 給Image對象繪製簽名
         * 3. 寫出Image對象到文件系統
         */
        InputStream in = new BufferedInputStream(new FileInputStream(src));
        BufferedImage image = ImageIO.read(in);
        in.close();

        Graphics g = image.getGraphics(); // 綁定畫筆
        g.setColor(new Color(0x55ffffff, true));
        g.setFont(new Font("幼圓", 1, 32));
        Date date = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        g.drawString(sdf.format(date), 30, 30);
        OutputStream out = new BufferedOutputStream(new FileOutputStream(dec));
        ImageIO.write(image, "jpg", out);
        out.close();