如何用zend_control链接多个路由

我的问题是如何使用Zend_Controller_Router_Route_Chain链接多条路由?

例如，我想链接年/月/日的3条路由但目标是:

<>之前当url为example.com/2011运行索引控制器，年份动作example.com/2011/11运行指数控制器，年-月动作example.com/2011/11/10运行指数控制器，年-月-日动作之前

我正在尝试使用这个代码:

$front = Zend_Controller_Front::getInstance();
$router = $front->getRouter();
$chain = new Zend_Controller_Router_Route_Chain();
$route1 = new Zend_Controller_Router_Route(
    ':year',
    array(
        'controller' => 'news',
        'action'     => 'year'
    )
);
$route2 = new Zend_Controller_Router_Route(
    ':month',
    array(
        'controller' => 'news',
        'action'     => 'year-month'
    )
);
$route3 = new Zend_Controller_Router_Route(
    ':day',
    array(
        'controller' => 'news',
        'action'     => 'year-month-day'
    )
);
$chain->chain($route1)
      ->chain($route2)
      ->chain($route3);
$router->addRoute('chain', $chain)
       ->addRoute('route3', $route3)
       ->addRoute('route2', $route2)
       ->addRoute('route1', $route1);

当我访问example.com/2012和example.com/2012/11/11时一切正常

但是当我访问example.com/2012/11/时，应用程序显示了年-月-日的操作，页面上有

<>之前注意:未定义的索引:P:'Zend'ZendServer'share'ZendFramework'library'Zend'Controller'Router'Route.php中的天之前

也许我做错了什么。请帮我解决我的问题。谢谢。

$route1 = new Zend_Controller_Router_Route(
    ':year/:month/:day',
    array(
        'controller' => 'news',
        'action'     => 'year',
        'year' => '0',
        'month' => '0',
        'day' => '0'
    )
);