How do I log into a google apps account associated with my custom application without prompting the user?

I'm wor开发者_JAVA百科king on a google apps based application - its a project management system and I'm setting it such that it requires a single google apps account to be used for all users of a particular installed instance. I.E someone installs it using a google apps account he/she can create users who can log in from a separate login screen. At the same time when these other users log in I would like to set it up so that when they log in to the system - the google app account they are associated with is automaticaly authenticated and they don't have to manually add in the username and password for that google apps account.

Any ideas here?

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yes you can do that without open id,but for that you must have user-id and password of both ie your website and his/her's google user-id and password. Then you just have to pass userid and password to google as url and u have to store session.Just like Phishing sites do