首先 配置 密鑰?

load->library('session');
		}
		public function index()
		{
			if($this->session->userdata('login'))
			{
				echo '已經(jīng)登陸';
			}
			else
			{
				echo '尚未登陸';
			}
		}
		public function login()
		{
			$this->session->set_userdata(array('login'=>'蜘蛛俠'));
		}
		public function loginout()
		{
			$this->session->unset_userdata('login');
		}
	}
?>