thanks for your answer? i am new in this (JPA) and reading your answer i think that i am missing somethig. reading your answer i think that into my code there is some thing missing. Can you help me please for geting my first example?
my classes are in https://dl.dropbox.com/u/3576658/Public.7z (2kb) and i only have 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); } Can you help me please. I cannot get started 2013/2/20 Rick Curtis <curti...@gmail.com> > 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.i...@gmail.com> wrote: > > > this: > > public void persist(E entity) { > > entityManager.persist(entity); ** this line > > } > > > > thanks for your answer > > > > > > 2013/2/20 Rick Curtis <curti...@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.i...@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* >
