Prevent Dozer from triggering Hibernate lazy loading

I am using Spring transactions so the transaction is still active when POJO to DTO conversion occurs.

I would like to prevent Dozer from triggering lazy loading, so that hidden sql queries never occur : all fetching has to be done explicitly via HQL (to get the best control on performances).

1. Is it a good practice (I can't find it documented anywhere) ?

2. How to do it safely ?

I tried this before DTO conversion :

PlatformTransactionManager tm = (PlatformTransactionManager) SingletonFactoryProvider.getSingletonFactory().getSingleton("transactionManager");
tm.commit(tm.getTransaction(new DefaultTransactionDefinition()));

I don't know what happens to the transaction, but the Hibernate session doesn't get closed, and the lazy loading still occurs.

I tried this :

SessionFactory sf = (SessionFactory) SingletonFactoryProvider.getSingletonFactory().getSingleton("sessionFactory");
sf.getCurrentSession().clear();
sf.getCurrentSession().close();

And it prevents lazy loading, but is it a good practice to manipulate session directly in the application layer (which is called "facade" in my project) ? Which negative side effects should I fear ? (I've already seen that tests involving POJO -> DTO conversions could no more be launched through AbstractTransactionnalDatasource Spring test classes, because this classes try to trigger a rollback on a transaction which is no more linked to an active session).

I've also tried to set propagation to NOT_SUPPORTED or REQUIRES_NEW, but it reuse the current Hibernate session, and doesn't prevent lazy loading.