FileUpload метка текста в кодировке utf 8

Question

Я работаю с angular 7 и при весенней загрузке. Я хочу сохранить файл с текстом арабского языка c. Я отправляю с фронта форму. Данные с помощью этого кода:

 const blob = new Blob([content], { type: "application/pdf ; charset=utf-8" });
          const reader = new FileReader();          
          reader.readAsDataURL(blob);
          this.formData.append('files', blob,fileName);

, и я использую из backend этот код:

@RequestMapping(value="/uploadFile/")
public UploadFile uploadFile(@RequestParam("files")  MultipartFile files) {
     try {
         log.debug("File : "+files);
         fileStorageProperties.setUploadDir("C:/");
         fileStorageLocation = Paths.get(fileStorageProperties.getUploadDir()) ;
           log.debug("dir"+fileStorageProperties.getUploadDir());
         Files.createDirectories(this.fileStorageLocation);
            log.debug("$$$$$",fileStorageProperties.getUploadDir());
            this.fileStorageService = new FileStorageService(this.fileStorageProperties);
        } catch (Exception ex) {
            throw new FileStorageException("Could not create the directory where the uploaded files will be stored.", ex);
        }
    String fileName = this.fileStorageService.storeFile(files);

    String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()
            .path("/api/upload-files/downloadFile/")
            .path(fileName)
            .toUriString();

    return new UploadFile(fileName, fileDownloadUri,
            files.getContentType(), String.valueOf(files.getSize()));
}




  public String storeFile(MultipartFile file) {
    // Normalize file name
    String fileName = StringUtils.cleanPath(file.getOriginalFilename());

    try {
        // Check if the file's name contains invalid characters
        if(fileName.contains("..")) {
            throw new FileStorageException("Sorry! Filename contains invalid path sequence " + fileName);
        }

        // Copy file to the target location (Replacing existing file with the same name)
        Set<PosixFilePermission> perms = new HashSet<PosixFilePermission>();
        //add owners permission
        perms.add(PosixFilePermission.OWNER_READ);
        perms.add(PosixFilePermission.OWNER_WRITE);
        perms.add(PosixFilePermission.OWNER_EXECUTE);

        Path targetLocation = this.fileStorageLocation.resolve(fileName);

        Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);

        return fileName;
    } catch (IOException ex) {
        throw new FileStorageException("Could not store file " + fileName + ". Please try again!", ex);
    }
}

но проблема в том, что текст arabi c не отображается в файле pdf