code: private String processUploadResponse(Response res) throws QiniuException {
  		if (res.isOK()) {
  			UploadResult ret = res.jsonToObject(UploadResult.class);
  			return getFullPath(ret.key);
  		}
  		throw new FSOperErrorException(name(), res.toString());
  	}
docs: 处理上传结果，返回文件url
  
  @return
  @throws QiniuException