Are you trying to secure the site? In which case you might be better off hooking up Spring Security into the project and have it manage the URL security for you.
But if you really want to map some view to the / then in your application context you can also add something like this
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">
<!--facilitates mapping of Dispatcher Servlet to /-->
<mvc:default-servlet-handler/>
<mvc:view-controller path="/" view-name="login"/>
</beans>
this will forward the / requests to the login view using parameterizable view controller
Still unsure of the reason why you would do something like this as Filter would be a better option even if you were wanting to do login/security check without Security frameworks.
Edit: here is how you can do it through controller itself
@RequestMapping("/")
@Controller
public class MyController {
@RequestMapping()
public String showMeTheLoginPage() {
return "redirect:/login.html";
}
}