private function __construct()
 {
     $this->appInfo =& getAppInfo();
     self::$root = $this->appInfo->system['root'];
     $this->result = array();
     $this->system = $this->appInfo->system;
     // TODO 载入默认语言的代码放在这里不太合适
     $this->language = array();
     $defaultLanguage = getConfig("language", "default");
     if (!empty($defaultLanguage)) {
         foreach (explode(",", $defaultLanguage) as $v) {
             $this->loadLanguage($v);
         }
     }
 }