openjpa-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Rick Curtis <curti...@gmail.com>
Subject Re: my fist openjpa porject / problem. help me please
Date Wed, 20 Feb 2013 15:04:42 GMT
Where is your EntityManager reference coming from? If you're using
injection, I'd suggest looking through the logs for any error / warning
messages that would help you figure out what is going on.


On Wed, Feb 20, 2013 at 1:50 AM, Aitor Iturriondobeitia <
laudio.info@gmail.com> wrote:

> this:
> public void persist(E entity) {
>  entityManager.persist(entity); ** this line
> }
>
> thanks for your answer
>
>
> 2013/2/20 Rick Curtis <curtisr7@gmail.com>
>
> > What is at com.caf.db.dao.JpaDao.persist(JpaDao.java:20)?
> >
> >
> > On Tue, Feb 19, 2013 at 5:08 PM, Aitor Iturriondobeitia <
> > laudio.info@gmail.com> wrote:
> >
> > > hello
> > > i an tring to build my firts openjpa app
> > > i am readint this article (
> > > http://java.dzone.com/articles/jpa-implementation-patterns) and
> building
> > > it
> > > for this i make this:
> > > 1.- generic interface:
> > > public interface IGenericDao<K, E> {
> > >  void persist(E entity);
> > > }
> > > 2.- other interface, my interface.
> > > public interface IWsSrvTrackRequest  extends IGenericDao<Integer,
> > > Wssrvtrackrequest>{
> > >  void wsSrvRequestPersist(Wssrvtrackrequest request);
> > > }
> > > 3.- generic JPA-DAO:
> > > public abstract class JpaDao<K, E> implements IGenericDao<K, E>
{
> > >  protected Class<E> entityClass;
> > >
> > >  @PersistenceContext
> > >  protected EntityManager entityManager;
> > >
> > >  public JpaDao() {
> > >   ParameterizedType genericSuperclass = (ParameterizedType)
> > > getClass().getGenericSuperclass();
> > >   this.entityClass = (Class<E>)
> > > genericSuperclass.getActualTypeArguments()[1];
> > >  }
> > >  public void persist(E entity) {
> > >   entityManager.persist(entity);
> > >  }
> > >  }
> > > }
> > > 4.- my jpa-dao implementation (the Wssrvtrackrequest obj is one jpa
> > object
> > > (entity)).
> > > public class JpaWsSrvTrackRequestDaoImpl extends JpaDao<Integer,
> > > Wssrvtrackrequest> implements IWsSrvTrackRequest {
> > >  public void wsSrvRequestPersist(Wssrvtrackrequest request){
> > >    entityManager.persist(request);
> > >  }
> > > }
> > > i am make one main class:
> > > public static void main(String[] args) {
> > >   IWsSrvTrackRequest r = new JpaWsSrvTrackRequestDaoImpl();
> > >   Wssrvtrackrequest v = new Wssrvtrackrequest();
> > >   v.setWssrvreqIp("la ip");
> > >   v.setWssrvreqOid("oid");
> > >   v.setWssrvreqOiduser("oiduser");
> > >   v.setWssrvreqRequest("la request");
> > >   r.persist(v);
> > >  }
> > >
> > >  but it always returns one nullpointerexception.
> > >  Exception in thread "main" java.lang.NullPointerException
> > >  at com.caf.db.dao.JpaDao.persist(JpaDao.java:20)
> > >  at com.caf.db.dao.ll.main(ll.java:20)
> > >
> > >  Can you help me please?
> > >
> > >  thanks
> > >
> >
> >
> >
> > --
> > *Rick Curtis*
> >
>



-- 
*Rick Curtis*

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message