Java Reference
In-Depth Information
Building an EJB 3.0
Persistence Model with
Oracle JDeveloper
Oracle Fusion Middleware is a family name for a set of Java EE products that are
integrated for SOA and web application deployment.
WebLogic
Server
(
WLS
) is the
Java EE container and Oracle JDeveloper the Java EE and SOA development IDE.
In this chapter, we will use JDeveloper to create an EJB 3.0 application, and then we
will deploy and test our application leveraging the embedded WebLogic Server that
comes with JDeveloper. This makes it very easy for us to develop, deploy, and test
our application.
WebLogic server 10.x provides some value-added features to facilitate EJB
3 development. WebLogic server 10.x supports automatic deployment of a
persistence unit based on the injected variable's name. The
@javax.persistence.
PersistenceContext
and
@javax.persistence.PersistenceUnit
annotations are used to inject the persistence context in an
EntityManager
or
EntityManagerFactory
variable. A persistence context is a set of entities that are
mapped to a database with a global JNDI name. If the name of the injected variable
is the same as the persistence unit, the
unitName
attribute of the
@PersistenceContext
or
@PersistenceUnit
is not required to be specified. The
EJB container automatically deploys the persistence unit and sets its JNDI name to
be the same as the persistence unit name in
persistence.xml
. For example, if the
persistence unit name in the
persistence.xml
file is
em
, an
EntityManager
variable
may be injected with the persistence context as follows:
@PeristenceContext
private EntityManager em;
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