[Java知识库]java生成图片带有字体水印（根据图片大小动态生成水印字体大小）

    /**
     * @param filePath         需要添加水印的图片地址
     * @param fileAddress      生成水印后的图片地址
     * @param watermarkingName 水印信息
     * @return
     */
    public static boolean addImageWatermarking(String filePath, String fileAddress, String watermarkingName) {
        try {
            File newFile = new File(filePath);
            Image image = ImageIO.read(newFile);/*将图片文件转换成图片*/
            int width = image.getWidth(null);/*获取文件的宽*/
            int height = image.getHeight(null);/*获取文件的高*/
            int size = width / 300 * 10;
            if (size == 0) {
                size = 10;
            }
            Font font = new Font("宋体", Font.BOLD, size);//水印字体，大小

            /*添加水印*/
            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D graphics = bufferedImage.createGraphics();
            graphics.drawImage(image, 0, 0, width, height, null);
            graphics.setColor(Color.lightGray);
            graphics.setFont(font);
            graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.5f));//设置水印透明度 默认为1.0  值越小颜色越浅
            graphics.rotate(Math.toRadians(-45), width, height);/*设置水印旋转*/

            JLabel label = new JLabel(watermarkingName);/*获取自定义水印信息*/
            FontMetrics metrics = label.getFontMetrics(font);
            int waterWidth = metrics.stringWidth(label.getText());//文字水印的宽
            int rowsNumber = (height / waterWidth) + (height % waterWidth);// 图片的高  除以  文字水印的宽  打印的行数(以文字水印的宽为间隔)
            int columnsNumber = width / waterWidth;//图片的宽 除以 文字水印的宽  每行打印的列数(以文字水印的宽为间隔)
            //防止图片太小而文字水印太长，所以至少打印一次
            if (rowsNumber < 1) {
                rowsNumber = 1;
            }
            if (columnsNumber < 1) {
                columnsNumber = 1;
            }
            for (int j = 0; j < rowsNumber; j++) {
                for (int i = 0; i < columnsNumber; i++) {
                    graphics.drawString(watermarkingName, i * waterWidth + j * waterWidth, -i * waterWidth + j * waterWidth);//画出水印,并设置水印位置
                }
            }
            graphics.dispose();
            /*输出图片 */
            FileOutputStream outputStream = new FileOutputStream(fileAddress);
            ImageIO.write(bufferedImage, "jpg", outputStream);
            outputStream.flush();
            outputStream.close();
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }