function ejson($code, $message, $data = array()){
    $data = $data ? $data : array();
    header('Content-Type:application/json; charset=utf-8');
    echo json_encode(array('code' => $code, 'message' => $message, 'data' => $data), JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
    exit();
}