xcode load xxxx.ExportJson error

Use macbook, xcode. I can load this json file correctly in full path , but when i used relative path, it will output the message “read json file[startPage_UI/startPage_UI.ExportJson] error!” .
My file is exist in “XXXXX/Resources/startPage_UI/startPage_UI.ExportJson”.
And relative path I used is “startPage_UI/startPage_UI.ExportJson”".
Is there any problem?

supplement:
My code is “auto ui = GUIReader::shareReader()->widgetFromJsonFile(”startPage_UI/startPage_UI.ExportJson“);”
The json file is produced by cocostudio.
I used cocos2d-x3.0alpha1

I have finished the problem.
The solution is that you no need to add the prefix path. You just use the file name, whatever the file is in “Resources/XX/XX/X”.
Maybe is because the cocos team simplify it.
Thanks a lot 2 all of u.