In the Google+ API there is a method to search for public friends.
However, I do not see a way to get user friends. Is there any way to get the Google+ user's friends?
There currently is no API access to circles and friends in Googel+. There is an open feature request you can star to get notified if an API method is added.
Alternatively you can use the Google Contacts API. This has the downside of being a scarier permission dialog because there is not a read only permission.
来源：https://stackoverflow.com/questions/10820536/get-google-plus-user-friends