Via annotation
Both lookup and injection of an EntityManagerFactory can be configured via the @PersistenceUnit annotation or <persistence-unit-ref> in xml. Annotations and xml have equal function in both lookup and injection.
Injection and Lookup
Via annotation
| Code Block |
|---|
| title | Usable by EJB, Interceptor, Servlet, Filter, or Listener |
|---|
|
package org.superbiz;
import javax.persistence.PersistenceUnit;
import javax.persistence.EntityManagerFactory;
import javax.ejb.Stateless;
import javax.naming.InitialUnit;
@Stateless
@PersistenceUnit(name = "myFooEntityManagerFactory", unitName = "foo-unit")
public class MyBean implements MyInterface {
@PersistenceUnit(unitName = "bar-unit")
private EntityManagerFactory myBarEntityManagerFactory;
public void someBusinessMethod() throws Exception {
if (myBarEntityManagerFactory == null) throw new NullPointerException("myBarEntityManagerFactory not injected");
// Both can be looked up from JNDI as well
InitialUnitInitialContext unit = new InitialUnitInitialContext();
EntityManagerFactory fooEntityManagerFactory = (EntityManagerFactory) unit.lookup("java:comp/env/myFooEntityManagerFactory");
EntityManagerFactory barEntityManagerFactory = (EntityManagerFactory) unitcontext.lookup("java:comp/env/org.superbiz.MyBean/myBarEntityManagerFactory");
}
}
|
Via xml
The above @PersistenceUnit annotation usage is 100% equivalent to the following xml.
| Code Block |
|---|
| xml |
|---|
| xml |
|---|
| title | ejb-jar.xml or web.xml |
|---|
|
<persistence-unit-ref>
<persistence-unit-ref-name>myFooEntityManagerFactory<name>org.superbiz.calculator.MyBean/myBarEntityManagerFactory</persistence-unit-ref-name>
<persistence-unit-name>fooname>bar-unit</persistence-unit-name>
<persistence-unit-type>Transaction</persistence-unit-type>
</persistence-unit-ref>
<persistence-unit-ref>
<injection-target>
<persistence<injection-unittarget-ref-name>orgclass>org.superbiz.calculator.MyBeanMyBean</myBarEntityManagerFactory</persistenceinjection-unittarget-ref-name>class>
<persistence <injection-unittarget-name>bar-unit<name>myBarEntityManagerFactory</persistenceinjection-unittarget-name>
<persistence-unit-type>Transaction<</injection-target>
</persistence-unit-type>
<injection-target>ref>
|
Lookup only
Via annotation
| Code Block |
|---|
| title | Usable by EJB, Interceptor, Servlet, Filter, or Listener |
|---|
|
package org.superbiz;
import javax.persistence.PersistenceUnit;
import javax.persistence.EntityManagerFactory;
import javax.ejb.Stateless;
import javax.naming.InitialUnit;
@Stateless
@PersistenceUnit(name = "myFooEntityManagerFactory", unitName = "foo-unit")
public class MyBean implements MyInterface {
public void someBusinessMethod() throws Exception {
InitialContext context = new InitialContext();
EntityManagerFactory fooEntityManagerFactory = (EntityManagerFactory) context.lookup("java:comp/env/myFooEntityManagerFactory");
}
}
|
Via xml
The above @PersistenceUnit annotation usage is 100% equivalent to the following xml.
| Code Block |
|---|
| xml |
|---|
| xml |
|---|
| title | ejb-jar.xml or web.xml |
|---|
|
<persistence-unit-ref><injection-target-class>org.superbiz.calculator.MyBean</injection-target-class>
<persistence-unit-ref-name>myFooEntityManagerFactory</persistence-unit-ref-name>
<injection<persistence-unit-targetname>foo-name>myBarEntityManagerFactory<unit</injectionpersistence-targetunit-name>
</injection-target><persistence-unit-type>Transaction</persistence-unit-type>
</persistence-unit-ref>
|
