public function jsonReturn($code, $msg = '', $data = null)
{
if ($msg === '') {
$msg = Constant::getMessage($code);
}
Yii::app()->request->setIsAjaxRequest(true);
header('Content-Type: application/json');
echo json_encode(array('code' => $code, 'msg' => $msg, 'data' => $data));
Yii::app()->end();
}