public function actionNet()
 {
     $model = new Statistics();
     $result = $model->getNet();
     $data = $model->convert_json($result);
     //var_dump($data);die;
     $title = json_encode(array('text' => '校园网'));
     return $this->render('pie', ['jsondata' => $data, 'title' => $title]);
 }