I keep getting NullPointerException. I am reading but over there is not
telling me how to user in another layer. Please, someone can give me some
help?
2009/10/22 Roan Brasil Monteiro <roanbrasil_at_gmail.com>
> Should I user @PersistenceContext EntityManager? to propagate to container
> all application?
>
>
> 2009/10/22 Marina Vatkina <Marina.Vatkina_at_sun.com>
>
>> All chapters under Persistence.
>>
>> Roan Brasil Monteiro wrote:
>>
>>> Chapter 24?
>>>
>>> 2009/10/22 Roan Brasil Monteiro <roanbrasil_at_gmail.com <mailto:
>>> roanbrasil_at_gmail.com>>
>>>
>>> Just a part. I have a JEE aplication and I would like to split the
>>> persistence part from my JPA class. Do you have some idea? I will
>>> take a look on the documentation.
>>>
>>>
>>> 2009/10/22 Marina Vatkina <Marina.Vatkina_at_sun.com
>>> <mailto:Marina.Vatkina_at_sun.com>>
>>>
>>> It depends on what you are trying to achieve in which type of an
>>> application. Did you look at the JPA cjapter in Java EE 5
>>> Tutorial?
>>>
>>> Roan Brasil Monteiro wrote:
>>>
>>> How should I resolve it? How should be my class? I am
>>> learning and I am trying to put the persistence part in DAO
>>> class.
>>>
>>> 2009/10/22 Marina Vatkina <Marina.Vatkina_at_sun.com
>>> <mailto:Marina.Vatkina_at_sun.com>
>>> <mailto:Marina.Vatkina_at_sun.com <mailto:Marina.Vatkina_at_sun.com
>>> >>>
>>>
>>>
>>>
>>> You can't inject anything in a class that is neither a
>>> Main class,
>>> nor a JavaEE component.
>>>
>>> -marina
>>>
>>>
>>> Roan Brasil Monteiro wrote:
>>>
>>> I have a class BaseDAO as bellow and I am getting
>>> NullPointerException on EntityManager em =
>>> emf.createEntityManager(); line from BaseDAO class,
>>> Can someone
>>> help me how to fix it?
>>>
>>> public class BaseDAO<T> {
>>>
>>> @PersistenceUnit(unitName = "citespacePU")
>>> EntityManagerFactory emf;
>>> public List<T> ListCountry(){
>>> EntityManager em =
>>> emf.createEntityManager();
>>> try{
>>> Query q = em.createQuery("Select c from
>>> Country c ");
>>> List<Country> c = q.getResultList();
>>> return (List<T>) c;
>>> }finally{
>>> if (em != null && em.isOpen()) {
>>> em.close();
>>> }
>>> } }
>>>
>>>
>>> }
>>>
>>> I have my Jersey resource class:
>>>
>>> @Path("/user/")
>>> public class UserResource {
>>> @GET
>>> @Produces("text/plain")
>>> public String registerUser(){
>>> BaseDAO<Country> countryDAO =
>>> new BaseDAO<Country>();
>>> List<Country> c = countryDAO.ListCountry();
>>> String y = "";
>>> for(Country x: c){
>>> y = y + ":" +x.getName();
>>> }
>>> return "[Country List]:"+y;
>>>
>>> }
>>>
>>> -- Atenciosamente,
>>>
>>> Roan Brasil Monteiro
>>> http://roanbrasil.wordpress.com/
>>>
>>>
>>>
>>>
>>>
>>> -- Atenciosamente,
>>>
>>> Roan Brasil Monteiro
>>> http://roanbrasil.wordpress.com/
>>>
>>>
>>>
>>>
>>>
>>> -- Atenciosamente,
>>>
>>> Roan Brasil Monteiro
>>> http://roanbrasil.wordpress.com/
>>>
>>>
>>>
>>>
>>> --
>>> Atenciosamente,
>>>
>>> Roan Brasil Monteiro
>>> http://roanbrasil.wordpress.com/
>>>
>>
>>
>
>
> --
> Atenciosamente,
>
> Roan Brasil Monteiro
> http://roanbrasil.wordpress.com/
>
--
Atenciosamente,
Roan Brasil Monteiro
http://roanbrasil.wordpress.com/