function display($_swoole_tpl_file = '')
    {
        if (empty($_swoole_tpl_file))
        {
            $_swoole_tpl_file = strtolower($this->swoole->env['mvc']['controller']) . '/' . strtolower($this->swoole->env['mvc']['view']) . '.php';
        }
        if (!is_file($this->template_dir . $_swoole_tpl_file))
        {
            Error::info('template error', "template file[" . $this->template_dir . $_swoole_tpl_file . "] not found");
        }
        extract($this->tpl_var);
        include $this->template_dir . $_swoole_tpl_file;
    }