I'm trying to update the libraries of my project (from Hibernate 3.2.1 GA to Hibernate 4.2.8)
This (complex) application use LAZY loading and get the object later only when we need it. -->it seems to work differently now because I get some org.hibernate.LazyInitializationException: could not initialize proxy - no Session
@Entity
@Table(name = "CLIENTS")
public class Clients {
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "INFOIDT", insertable = true, updatable = false)
private Information info;
//...
}
and when I need to know more about the product before using it :
cli.getInfo();
Note that in my persistence.xml I also have the property hibernate.cache.provider_class set to org.hibernate.cache.EhCacheProvider for a second level cache.
QUESTION : what is the simple way to migrate my existing code with Hibernate4? (the class given for example above is a fake example to illustrate the many cases using the LAZY loading) Thank you.
As requested, see my DAO below :
public class MyAppJpaDAO extends GenericJpaDAO implements IMyAppDAO {
protected static Log log = LogFactory.getLog(MyAppJpaDAO.class);
// Entity Manager of the project
@PersistenceContext(unitName = "MyApp.hibernate")
private EntityManager em;
public News readLastNews() {
StringBuffer sql = new StringBuffer("");
sql.append(" select object(n) ");
sql.append(" from News n ");
sql.append(" Where n.flagLastStatus = 'V' ");
sql.append(" order by n.pk.date desc ");
Query aQuery = em.createQuery(sql.toString());
List<News> res = (List<News>) aQuery.getResultList();
if (res != null && res.size() != 0) {
return res.get(0);
}
return null;
}
//...
}
/////////////
public class GenericJpaDAO implements IGenericDAO {
protected static Log log = LogFactory.getLog(GenericJpaDAO.class);
@PersistenceContext(unitName = "MyApp.hibernate")
EntityManager em;
public Object getReference(Class _class, Object _object) {
return em.getReference(_class, _object);
}
public void createObject(Object object) {
try {
em.persist(object);
} catch (LazyInitializationException lie) {
em.merge(em.merge(object));
}
}
public void deleteObject(Object object) {
try {
em.remove(object);
} catch (Exception e) {
em.remove(em.merge(object));
}
}
public void updateObject(Object object) {
em.merge(em.merge(object));
}
//...
}
