Spring MVC将文件永久上传到服务器

Question

我正在尝试将文件上传到服务器上，但是每次启动应用程序时，它都会在服务器中创建一个文件夹，然后在该文件夹中上传文件。如何存储永久上传的文件，以便每当我启动应用程序时，它就会使用现有文件以获得更多功能，或询问用户服务器上是否不存在该功能。

@RequestMapping(value = "/upload", method = RequestMethod.POST)
public String index(Model model, @RequestParam("file") MultipartFile[] files,RedirectAttributes rm) {
    List<String> ls = new ArrayList<>();


    try {

        for (int i = 0; i < files.length; i++) {

            if (!files[i].isEmpty()) {
                 System.out.println("sdfghjk");
                ls.add(files[i].getOriginalFilename());

                byte[] bytes = files[i].getBytes();

                // Creating the directory to store file
                String rootPath = System.getProperty("catalina.home");
                File dir = new File(rootPath + File.separator + "tmpFiles");
                if (!dir.exists())
                    dir.mkdirs();

                // Create the file on server
                File serverFile = new File(dir.getAbsolutePath() + File.separator + files[i].getOriginalFilename());
                BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverFile));
                stream.write(bytes);
                stream.close();

                logger.info("Server File Location=" + serverFile.getAbsolutePath());
            } else {
                rm.addFlashAttribute("error","all the fies are needded");
                return "redirect:/uploadForm";
            }
        }
        model.addAttribute("list", ls);
        model.addAttribute("message", "succsesfully uploaded");
        return "NewFile";
    } catch (Exception e) {

        model.addAttribute("message", "failed to upload");
        System.out.println("catch");
        return "NewFile";
    }

}