java pdf转png 并拼接图片

    
    public static void test(String pdfPath, String imgPath, int mergeType) throws IOException {
        //利用PdfBox生成图像
        PDDocument pdDocument = PDDocument.load(new File(pdfPath));
        PDFRenderer renderer = new PDFRenderer(pdDocument);

        // 获取pdf总页数
        int pdfPages = pdDocument.getNumberOfPages();

        // 图片集合
        BufferedImage[] bufferedImageArray = new BufferedImage[pdfPages];

        for (int i = 0; i < pdfPages; i++) {
            // 第一张
            BufferedImage image = renderer.renderImageWithDPI(i, 200, ImageType.RGB);

            // 获取图像的宽度和高度
            int width = image.getWidth();
            int height = image.getHeight();

            // 获取计算好的rgb
            int[] rgb = image.getRGB(0, 0, width, height, null, 0, width);

            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

            // 写入流中
            bufferedImage.setRGB(0, 0, width, height, rgb, 0, width);

            // 添加到数组
            bufferedImageArray[i] = bufferedImage;

        }

        int[][] ImageArrays = new int[bufferedImageArray.length][];
        for (int i = 0; i < bufferedImageArray.length; i++) {
            int width = bufferedImageArray[i].getWidth();
            int height = bufferedImageArray[i].getHeight();
            ImageArrays[i] = new int[width * height];
            ImageArrays[i] = bufferedImageArray[i].getRGB(0, 0, width, height, ImageArrays[i], 0, width);
        }

        // 获取拼接尺寸
        int newHeight = 0;
        int newWidth = 0;
        for (int i = 0; i < bufferedImageArray.length; i++) {
            // 横向
            if (mergeType == 1) {
                newHeight = Math.max(newHeight, bufferedImageArray[i].getHeight());
                newWidth += bufferedImageArray[i].getWidth();
            }
            // 纵向
            else if (mergeType == 2) {
                newWidth = Math.max(newWidth, bufferedImageArray[i].getWidth());
                newHeight += bufferedImageArray[i].getHeight();
            }
        }

        // 新图片
        BufferedImage ImageNew = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
        int height_i = 0;
        int width_i = 0;
        for (int i = 0; i < bufferedImageArray.length; i++) {
            if (mergeType == 1) {
                // set新图片得RGB数据
                ImageNew.setRGB(width_i, 0, bufferedImageArray[i].getWidth(), newHeight, ImageArrays[i], 0, bufferedImageArray[i].getWidth());
                width_i += bufferedImageArray[i].getWidth();
            } else if (mergeType == 2) {
                ImageNew.setRGB(0, height_i, newWidth, bufferedImageArray[i].getHeight(), ImageArrays[i], 0, newWidth);
                height_i += bufferedImageArray[i].getHeight();
            }

        }
        // 输出图片
        ImageIO.write(ImageNew, "png", new File(imgPath + File.separator + StringUtils.getRandomNumber() + ".png"));
    }