Spring has a nice feature, which is often overlooked: a bean with shorter life-cycle can be injected into a bean with a longer life-cycle. A classic example is singleton for MVC controller and a request-scope bean for DAL. This is achieved in Spring with defining a proxy bean like this:

<bean id="booksDao" class="my.dal.BooksDao" scope="request">
  <aop:scoped-proxy />
</bean>

<bean id="booksFacade" class="my.web.BooksFacade">
  <property name="dao" ref="booksDao"/>
</bean>

This way, booksDao can be accessible from any beans processing the request, and Spring will ensure it's the same instance during the same request, and different instance for different requests.