Graphics2D绘制多图片水印方法

大家好，又见面了，我是你们的朋友全栈君。

还有一篇文章添加多种水印（文字水印(带背景颜色) +图片水印）大家可以看一下、
https://blog.csdn.net/whiteGu/article/details/97653571

/**
     * @param srcPath 需要添加水印的完整地址
     * @param ids     需要添加的水印的id集合 ，结果以 ","分隔
     * @return 返回包含水印图片的输入流
     * @throws Exception
     */
    public InputStream addWatermark(String srcPath, String ids) throws Exception {
        File waterFile1 = null;
        File waterFile2 = null;
        Image watermarkImage1 = null;
        Image watermarkImage2 = null;
        String fileSuffix = srcPath.substring(srcPath.lastIndexOf(".") + 1);
        if (StringUtils.isBlank(ids)) throw new BaseAppException("必传水印id");
        List<SysWatermark> sysWatermarks = Arrays.stream(ids.split(",")).map(x -> sysWatermarkService.getByPrimaryKey(x)
        ).collect(Collectors.toList());
        if (CollectionUtils.isEmpty(sysWatermarks)) throw new BaseAppException("没有对应的水印模板");

        //获取图片路径
        String waterImagePath1 = imgPrefix + sysWatermarks.get(0).getWatermarkUrl();
        File srcFile = new File(srcPath);
        waterFile1 = new File(waterImagePath1);
        if (sysWatermarks.size() > 1) {
            String waterImagePath2 = imgPrefix + sysWatermarks.get(1).getWatermarkUrl();
            waterFile2 = new File(waterImagePath2);
        }
        //读取原图片
        try {
            Image srcImage = ImageIO.read(srcFile);
            int height = srcImage.getHeight(null);
            int width = srcImage.getWidth(null);
            if (width > 1000 || height > 1000) {
                throw new BaseAppException("图片大小最大不能大于1000*1000");
            }
            //准备画板
            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            //创建画笔
            Graphics2D graphics = bufferedImage.createGraphics();
            graphics.drawImage(srcImage, width, height, null);
            //读取水印
            Image temp1 = ImageIO.read(waterFile1);
            ImageIcon imageIcon1 = new ImageIcon(temp1);
            watermarkImage1 = imageIcon1.getImage();
            //读取第二张水印
            if (null != waterFile2) {
                Image temp2 = ImageIO.read(waterFile2);
                ImageIcon imageIcon2 = new ImageIcon(temp2);
                watermarkImage2 = imageIcon2.getImage();
            }
            //第一张水印图片的透明度
            watermarkCoordinate(graphics, sysWatermarks.get(0), watermarkImage1, width, height);
            //处理第二张水印(如果是多水印可以采用循环方式，由于我这里只会有2张水印所以写死了)
            if (null != watermarkImage2) {
                watermarkCoordinate(graphics, sysWatermarks.get(1), watermarkImage2, width, height);
            }
            graphics.dispose();
             //本地测试
            OutputStream outputStream = new FileOutputStream("D:/test.jpg");
            ImageIO.write(bufferedImage, "JPG", outputStream);
            //本地测试结束(如果是本地测试下面不需要)
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage, fileSuffix, os);
            return new ByteArrayInputStream(os.toByteArray());
        } catch (IOException e) {
            e.printStackTrace();
            throw new BaseAppException("读取图片失败");
        }
    }

    /**
     * 添加水印管理
     *
     * @param graphics     画笔
     * @param sysWatermark 水印
     * @param image        水印图片
     * @param width        需要添加水印图的宽度
     * @param height       需要添加水印图的高度
     */
    private void watermarkCoordinate(Graphics2D graphics, SysWatermark sysWatermark, Image image, int width, int height) {
        float transparency = sysWatermark.getWatermarkTransparency() / 100;
        graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, transparency));
        //放上水印图
        String coordinate = sysWatermark.getWatermarkCoordinate();
        JSONObject parseObject = JSONObject.parseObject(coordinate);
        int watermarkWidth = (int) parseObject.get("width");
        int watermarkHeight = (int) parseObject.get("height");
        graphics.drawImage(image, width * watermarkWidth / 100, height * watermarkHeight / 100, null);
    }