Java 利用pdfbox将图片和成到pdf指定位置

业务背景：用户在手机APP上进行签名，前端将签完名字的图片传入后端，后端合成新的pdf.

废话不多说，上代码：

//控制层代码
    @PostMapping("/imageToPdf")
    public Result imageToPdf(@RequestParam("linkName") String name, @RequestParam("file") 
                                               MultipartFile file) throws IOException {
        try {
            String format = LocalDateTimeUtil.format(LocalDateTime.now(), 
            DatePattern.PURE_DATETIME_MS_PATTERN);
            File f = convertMultipartFileToFile(file);
            //缩放图片
            ImgUtil.scale(FileUtil.file(f), FileUtil.file("/hetong/dev/image/" + format + 
              ".png"), 0.06f);
            // 旋转270度
            BufferedImage image = (BufferedImage) 
//此处利用hutool工具类进行缩放
            ImgUtil.rotate(ImageIO.read(FileUtil.file("/hetong/dev/image/" + format + 
            ".png")), 270);
            ImgUtil.write(image, FileUtil.file("/hetong/dev/image/" + format + "_result" + 
            ".png"));
            String imagePath = "/hetong/dev/image/" + format + "_result" + ".png";
            String fileUrl = name; // 要下载的文件的HTTPS链接
            String localFilePath = "/hetong/dev/" + format + ".pdf"; // 下载文件保存到本地的路径和名称
            //String localFilePath = "D:\\soft\\ceshi\\" + format + ".pdf"; // 下载文件保存到本地的路径和名称
            downloadFile(fileUrl, localFilePath);
            String pdfPath = localFilePath;
            String url = imageToPdfUtil.addImageToPDF(imagePath, pdfPath, format);
            return new Result(ResultCode.SUCCESS, url);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new Result(ResultCode.IMAGE_MERGE_FAILED, "");
    }
 
 
//工具类
@Component
public class ImageToPdfUtil {
    private static Logger logger = LoggerFactory.getLogger(WordUtil.class);
    @Autowired
    private UploadManager uploadManager;
    @Autowired
    private Auth auth;
 
    @Value("${qiniu.bucketName}")
    private String bucketName;
    @Value("${qiniu.path}")
    private String url;
 
    /**
     * 添加图片至pdf指定位置
     *
     * @param imagePath
     * @param pdfPath
     * @throws IOException
     */
    public String addImageToPDF(String imagePath, String pdfPath, String format) throws IOException {
        // 加载图片
        PDDocument document = PDDocument.load(new File(pdfPath));
        PDPage lastPage = document.getPage(document.getNumberOfPages() - 1);
        PDImageXObject image = PDImageXObject.createFromFile(imagePath, document);
 
        // 获取图片宽度和高度
        float imageWidth = image.getWidth();
        float imageHeight = image.getHeight();
 
        try (PDPageContentStream contentStream = new PDPageContentStream(document, lastPage, PDPageContentStream.AppendMode.APPEND, true, true)) {
            // 设置图片位置
            float x = (lastPage.getMediaBox().getWidth() / 2f - imageWidth / 2f) * 0.88f;
            float y = (lastPage.getMediaBox().getHeight() / 2f - imageHeight / 2f) * 1.5f;
 
            // 添加图片到指定位置
            contentStream.drawImage(image, x, y, imageWidth, imageHeight);
        }
 
        // 保存修改后的 PDF
        document.save(pdfPath);
        document.close();
        return uploadQiniu(format);
    }
 
    /**
     * 上传到七牛云
     *
     * @param fileName
     * @return
     * @throws FileNotFoundException
     * @throws QiniuException
     */
    public String uploadQiniu(String fileName) throws FileNotFoundException, QiniuException {
        //这里是上传到服务器路径下的，已经填充完数据的word
        File file = ResourceUtils.getFile("/hetong/dev/" + fileName + ".pdf");
        //File file = ResourceUtils.getFile("D:\\soft\\ceshi\\" + fileName + ".pdf");
        //FileInputStream uploadFile = (FileInputStream) file.getInputStream();
        // 获取文件输入流
        FileInputStream inputStream = new FileInputStream(file);
 
        //这个是已经填充完整的数据后上传至七牛云链接
        String path = "http://" + upload(inputStream, fileName);
        logger.info("上传至七牛云的合同路径==path==" + path);
        return path;
    }
 
    public String upload(FileInputStream file, String fileName) throws QiniuException {
        String token = auth.uploadToken(bucketName);
        Response res = uploadManager.put(file, fileName, token, null, null);
        if (!res.isOK()) {
            throw new RuntimeException("上传七牛云出错:" + res);
        }
        return url + "/" + fileName;
    }
 
    public static void main(String[] args) {
        try {
            // 指定原始图片路径
            File originalImage = new File("D:\\soft\\ceshi\\20230901204201606.png");
 
            // 指定压缩后保存的目标路径
            File compressedImage = new File("D:\\soft\\ceshi\\20230901204201606_result.png");
 
            // 压缩和缩放图片
            Thumbnails.of(originalImage)
                    .scale(0.1) // 缩放比例为50%
                    .outputQuality(0.9) // 图片质量为80%
                    .toFile(compressedImage);
 
            System.out.println("图片压缩和缩放完成！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    /**
     * MultipartFile 转file
     *
     * @param multipartFile
     * @return
     * @throws IOException
     */
    public static File convertMultipartFileToFile(MultipartFile multipartFile) throws IOException {
        byte[] fileBytes = multipartFile.getBytes();
 
        File tempFile = File.createTempFile("temp", null);
        try (OutputStream outputStream = new FileOutputStream(tempFile)) {
            outputStream.write(fileBytes);
        }
        return tempFile;
    }
 
    /**
     * 根号https链接下载文档
     *
     * @param fileUrl
     * @param localFilePath
     * @throws IOException
     */
    public static void downloadFile(String fileUrl, String localFilePath) throws IOException {
        URL url = new URL(fileUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
 
        BufferedInputStream inputStream = new BufferedInputStream(connection.getInputStream());
        FileOutputStream outputStream = new FileOutputStream(localFilePath);
 
        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
        outputStream.close();
        inputStream.close();
        connection.disconnect();
    }
 
}

注意：前端传过来的图片必须是透明的，否则合成的时候签名处会有边框