1 MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
2 Map<String,MultipartFile> files = multipartRequest.getFileMap();

/**
     * @Title uploadFiles
     * @Description 測試多文件上傳
     * @date 2018-11-10 10:15
     */
    @PostMapping("/uploadFiles")
    public Map<String, Object> uploadFiles(HttpServletRequest req) {
        MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) req;
        // 無須知道上傳時文件對應的key，遍歷處理
        Map<String, MultipartFile> files = multipartRequest.getFileMap();
        String otherParam = req.getParameter("otherParam");
        Map<String, Object> data = new HashMap<>();
        for (MultipartFile value : files.values()) {
            data = uploadFile(value);
            int code = (int) data.get("code");
            if (200 != code) {
                return data;
            }
        }
        data.put("code", 200);
        data.put("result", otherParam);
        return data;
    }

    /**
     * @Title uploadFile
     * @Description 逐個上傳
     * @date 2018-11-10 10:17
     */
    private Map<String, Object> uploadFile(MultipartFile file) {
        Map<String, Object> result = new HashMap<>();
        // 判斷文件是否為空
        if (file.isEmpty()) {
            result.put("code", -1);
            return result;
        }
        String fileName = file.getOriginalFilename();
        // 原文件名前加時間戳和隨機數，避免覆蓋文件
        String path = "D:/temp/" + new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
        path = path + ((int) Math.random() * 999) + "_" + fileName;
        File dest = new File(path);
        if (dest.exists()) {
            result.put("code", -2);
            return result;
        }
        // 判斷文件父目錄是否存在
        if (!dest.getParentFile().exists()) {
            dest.getParentFile().mkdir();
        }
        try {
            file.transferTo(dest); // 保存文件
        } catch (IOException e) {
            result.put("code", -3);
            return result;
        }
        result.put("code", 200);
        return result;
    }