/**
  * 根据Zend_Navigation_Page对象生成资源字符串
  * 
  * @static
  * @param Zend_Navigation_Page $page
  * @return string
  */
 public static function parseNavigationPage(Zend_Navigation_Page $page)
 {
     if ($page instanceof Zend_Navigation_Page_Mvc) {
         $mvc = array($page->getModule(), $page->getController(), $page->getAction());
         return implode(self::SEPARATOR, array_filter($mvc));
     } else {
         if ($page instanceof Zend_Navigation_Page_Uri) {
             return self::parseUri($page->getUri());
         }
     }
     return $page->getResource();
 }