Can I use get to avoid LazyInitializationException?

Nicsoft · **Joined:** Thu Feb 19, 2009 12:24 pm **Posts:** 14

Hello,

I am creating some functionality such as that I want to retreive an object from the database, then close the session, then use the object. The problem when doing this is if I use "load" to the get object I can not use it after the session is closed. BUT, if I use "get" to retreive the object from the database then it works just fine.

When I was searching on different forums they all pointed out that one should set lazy="false" to fix this and that doing this may have impact on performance. None mentioned anything about using "get" instead to retreive the object. Don't know if that solves a different source for the problem than mine and, hence, if it would have solved my problem.

The questions: Is there any reason not using "get" or is it just fine? Is there any difference except that "load" isn't actually loading the object/properties before you need it?

My original problem was that I want to have a nice, generic method which can be used to fetch different kind of objects from the database. Of cours, when returning to the parent method the session is closed, hence my problem. Is this a good way of solving the problem (both using get and the design) and then continueing in the parent method's session (that is used to continue updating the object in the database) or should I pass the session into the child method and use it as well?

I am kind of new in my efforts trying to create "great designs" so any comments is most appreciated.

Thank you in advance!

Regards,
Niklas

iririr · **Joined:** Thu Mar 19, 2009 8:19 pm **Posts:** 12

take a look at this, it might help

http://gmarwaha.blogspot.com/2007/01/hi ... sions.html

mystic · **Joined:** Tue May 12, 2009 6:08 am **Posts:** 92

When you query the database, have a boolean value available - something like "loadEntity"

So after your query, you go:

Code:

if( loadEntity ) Hibernate.initialize( myParent.getEntities() );

return myParent;

This will load the collection before the session is up. This way you only load the children if you want to in your dao/service layer. If every part of your app needs those entities to be loaded, then you don't need the parameter.

Also, you can use fetch join in your query string, which is pretty fast and doesn't hamper performance all that much. It avoids multiple calls to the database.

It's written like this:

Code:

from MyParent parent fetch join parent.getEntities where ....

I hope that helps.