我找到了一个很好的资源页面，可以满足您的需求:
http://particul.es/blog/index.php?post/How-to-change-backend.php-to-admin-prefix-routes-automatically-symfony
提供多种解决方案来实现您的目标.但是，就个人而言，我认为对您来说最明智的方法是在 .htaccess 中处理此问题.

I have found a great ressource page for your needs:
http://particul.es/blog/index.php?post/How-to-change-backend.php-to-admin-prefix-routes-automatically-symfony
With many solutions to achieve your goals. But, personnaly, I think that the smartest way for you is to handle this in .htaccess.