Why EntityManager have null value in my dao layer? - jpa

Question

I'm working on a Java EE 7 maven project I'm using wildfly 8.2 everything is okey the problem is when I create an entity manager using #PersistenceContext inside managedbeans (backing beans) that I use with my jsf the contanier create a entit manager object and it's work but when I try to use the entity maanger inside my DAO Layer it's not work the em stay have a null value and I don't know why this my code in my dao layer can someone helpe me ? .
dao interface :
public interface ICategoryDao {
Category addCategory(Category category);
void deleteCategory(Long codeCategory);
Set<Category> getAllCategories();
Category updateCategory(Category category);
}
dao impl :
#Named("categoryDao")
public class CategoryDao implements ICategoryDao{
private Logger log = Logger.getLogger(CategoryDao.class);
#PersistenceContext(unitName="BooksStore")
private EntityManager em ;
#Override
public Category addCategory(Category category) {
if(em==null)
{
log.info("em is null ");
return category;
}
em.getTransaction().begin();
em.persist(category);
em.getTransaction().commit();
log.info("CategoryDao : Object persisted." );
return category;
}
#Override
public void deleteCategory(Long codeCategory) {
// TODO Auto-generated method stub
}
#Override
public Set<Category> getAllCategories() {
// TODO Auto-generated method stub
return null;
}
#Override
public Category updateCategory(Category category) {
// TODO Auto-generated method stub
return null;
}
}
this is my beans.xml
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd" bean-discovery-mode="all">
</beans>
My persistance.xml file :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="BooksStore" transaction-type="JTA">
<jta-data-source>java:/bookstore</jta-data-source>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.hbm2ddl.auto" value="update" />
</properties>
</persistence-unit>
</persistence>

Answer 1

Do you have a persistence.xml file ?
This is an example for persistence.xml file :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="School_Manager" transaction-type="RESOURCE_LOCAL">
<class>YourEntityFQN</class>
<properties>
attribute name on persistence.xml file must be "BooksStore" in your case .
In class tag you need to specify all entity that you want use for this persistence-unit .