Swift单例

class TestObject{

         private static let testObject = TestObject()

         static var shareInstance: TestObject{

                  return testObject

         } 

         private init(){

         }

}

class MyManager{

        static let shareInstance = MyManager()

        private init(){}

}

private static let instance = NetworkTools()

/// 在 swift 中类变量不能是存储型变量

class var sharedNetworkTools: NetworkTools {

return instance

}

override init() {

println("come baby")

}

}