feat: 完善对象存储文档

开发文档/LDP第三方对象存储服务使用说明.md

@@ -70,9 +70,12 @@ StorageService storageService;
 
 @Override
 public String uploadToCloudStorage(MultipartFile file) {
+    if (file == null) {
+        throw new BizException(500, "文件不能为空");
+    }
     String uploadPath = null;
     try {
-        //调用上传方法，返回的是下载地址
+        //调用上传方法，返回下载地址
         uploadPath = storageService.upload(file.getBytes(), file.getOriginalFilename());
     } catch (Exception e) {
         e.printStackTrace();