I have went through google api documentation and so many reference links. but i have never seen related to google plus post message. In Google API Documentation They shows
Note: The Google+ API currently provides read-only access to public data. All API calls require either an OAuth 2.0 token or an API key.
Is there any other way to implement this?. Please, can any one help me?
That means the API is read-only. You cannot post anything on Google+ through the API as of the time of this writing.