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/