代码

    public static String APP_UPLOAD_EXTERNAL = "G:\\temp";
    private String filePathPrefix = "";
 @RequestMapping(value = "/uploadImage", method = RequestMethod.POST)
    @SJson
    public Object image(@RequestParam("Filedata") MultipartFile tf, HttpServletRequest request) {
        String u = StringUtils.trimToEmpty(request.getParameter("u"));
        System.out.print("temp:" + request.getSession().getServletContext().getRealPath("uploadTemp/"));
        boolean isUrl = StringUtils.isBlank(u) || Boolean.parseBoolean(u) || u.equals("1");
        if (!tf.isEmpty()) {
            List<String> imageList = config.getList("upload.suffix.image", ",");
            if (imageList.contains(tf.getOriginalFilename().substring(tf.getOriginalFilename().lastIndexOf(".") + 1))) {
                filePathPrefix = Globals.APP_UPLOAD_EXTERNAL + "\\image\\";
                return upload(tf, isUrl);
            } else {
                return Result.error("globals.upload.suffix");
            }
        }
        return Result.error("globals.upload.fail");
    }
    private Result upload(MultipartFile tf, boolean isUrl) {
        try {
            String uploadMode = config.get("upload.mode", "file");
//            String fileName = tf.getOriginalFilename();
            String fileName = R.UU32() + tf.getOriginalFilename().substring(tf.getOriginalFilename().lastIndexOf("."));
            String fileExtName = fileName.substring(fileName.lastIndexOf(".") + 1);
            if ("fdfs".equalsIgnoreCase(uploadMode)) {
                //如果使用文件服务器
                byte[] fileBuff = tf.getBytes();
                ClientGlobal.init(config);
                //建立连接
                TrackerClient tracker = new TrackerClient();
                TrackerServer trackerServer = tracker.getConnection();
                StorageServer storageServer = null;
                StorageClient1 client = new StorageClient1(trackerServer, storageServer);
                //设置元信息
                NameValuePair[] metaList = new NameValuePair[3];
                metaList[0] = new NameValuePair("fileName", fileName);
                metaList[1] = new NameValuePair("fileExtName", fileExtName);
                metaList[2] = new NameValuePair("fileLength", String.valueOf(tf.getSize()));

                //上传文件
                String fdfsFileId = client.upload_file1(fileBuff, fileExtName, metaList);

                // 存进数据库
                Sys_file sysFile = new Sys_file();
                sysFile.setName(fileName);
                sysFile.setSize(tf.getSize());
                sysFile.setType(tf.getContentType());
                sysFile.setUrl(config.get("fdfs.domain", "") + "/" + fdfsFileId);
                sysFile.setId(R.UU32());
                sysFile.setFdfs_file_id(fdfsFileId);
                sysFile = sysFileService.insert(sysFile);
                if (isUrl) {
                    return Result.success("globals.upload.success", sysFile.getUrl());
                } else {
                    return Result.success("globals.upload.success", sysFile);
                }
            } else {
                //String p = Globals.APP_ROOT;
                String fileId = R.UU32();
                if (filePathPrefix.equals("")) {
                    filePathPrefix = Globals.APP_UPLOAD_PATH + "/file/";
                }
                String f = filePathPrefix + DateUtil.format(new Date(), "yyyyMMdd") + "\\" + fileId + "." + fileExtName;
                System.out.print("f:" + f);
                tf.transferTo(Files.createFileIfNoExists(f));
                // 存进数据库
                Sys_file sysFile = new Sys_file();
                sysFile.setName(fileName);
                sysFile.setSize(tf.getSize());
                sysFile.setType(tf.getContentType());
                sysFile.setUrl(Globals.APP_BASE + "/open/file/download/" + fileId);
                sysFile.setId(fileId);
                sysFile.setPath(f);
                sysFile = sysFileService.insert(sysFile);
                if (isUrl) {
                    return Result.success("globals.upload.success", sysFile.getUrl());
                } else {
                    sysFile.setPath("");
                    return Result.success("globals.upload.success", sysFile);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            return Result.error("globals.upload.error");
        }
    }

可以正常上传了，多谢！

 //String p = Globals.APP_ROOT;
                String fileId = R.UU32();
                if (filePathPrefix.equals("")) {
                    filePathPrefix = Globals.APP_UPLOAD_PATH + "/file/";
                }
                String f = filePathPrefix + DateUtil.format(new Date(), "yyyyMMdd") + "\\" + fileId + "." + fileExtName;
                new File(f).createNewFile();
                // 换行并打印
                System.out.println();
                System.out.println("Path=[" + f + "]");
                tf.transferTo(Files.createFileIfNoExists(f));

输出：Path=[G:\temp\image\20180906\7irm15o2foh90pfl91ae0nchea.jpg]

嗯！测试正常了，可以正确创建文件夹了……多谢大佬！