lazy loading with Spring data

Question

I'm using Spring data which is easy to use but i can't control it because i got error there

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: entity.Qualite.fonctions, could not initialize proxy - no Session

I know FetchType.EAGER will work but i want keep it lazy. so how can i control the session in spring data

@RequestMapping(value="/loadfonction") 
public @ResponseBody
Set<Fonction> loadfonction(Map<String, Object> model, HttpServletRequest request) { 

    Set<Fonction> fonctions = qualiteRepo.findOne(Integer.valueOf(request.getParameter("idquality"))).getFonctions();

    System.out.println(fonctions.size());

    return fonctions;


}

I even try @Transactional annotation but it didn't work:

@Transactional
@RequestMapping(value="/loadfonction")

Jimmy Johnson · Accepted Answer · 2014-01-22 23:30:04Z

2

This is a common problem with trying to open a view using the spring mvc framework. The control method closes the session before the view can display it. (Trying to keep the view out of the business logic) To get around it you can use the OpenSessionInViewFilter class.

Here is an article on how to implement it:

http://blog.cloudmate.pl/2010/09/hibernates-open-session-in-view-in.html

answered Jan 22, 2014 at 23:30

Jimmy Johnson

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2 Comments

Hayi Over a year ago

the problem is not in the view level.

Matt Byrne Over a year ago

Jimmy is right, the problem is around your transactional boundaries. @Transactional should be at your service layer (business methods should be transactional, not finer-grained DAO/Repository methods) and you should ideally not be exposing JPA entities beyond your service layer (beyond the transactional/session boundaries). OpenSessionInViewFilter is a workaround to an imperfect design.

Vaelyr · Accepted Answer · 2014-01-23 14:06:43Z

2

In your repository you cannot use query methods to initialize the collection. Instead you should define a query like that to fetch the collection with it. Change your query according to your domain, I can't really figure out how it should look for you.

@Query("SELECT q FROM Qualite q JOIN FETCH q.role WHERE q.fonctionId = (:fonctionId)")
public Qualite findById(@Param("fonctionId") String fonctionId);

answered Jan 23, 2014 at 14:06

Vaelyr

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Comments

JCalcines · Accepted Answer · 2014-01-22 23:16:26Z

1

You can't. The only way to avoid this problem is to do a query when you want to retrieve the Fonction objects.

answered Jan 22, 2014 at 23:16

JCalcines

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2 Comments

Hayi Over a year ago

it's impossible with spring data or also if i migrate to hibernate where i can control session and transaction ?

JCalcines Over a year ago

I'm not sure about it but, I think if you are in a transaction you can call to some method to reload the lazy collection. I read something of that many time ago but I never used it.

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