我想出了如何检索登录用户的名字/姓氏。有没有办法获得AppleID?!
var defaultContainer = CKContainer.defaultContainer()
var publicDatabase = defaultContainer.publicCloudDatabase
defaultContainer.discoverUserInfoWithUserRecordID(recordID, {userInfo, error in
println("firstName: \(userInfo.firstName?) lastName: \(userInfo.lastName?)")
})