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Is it possible to override persistence.xml properties via configuration ?

Answer 1

A:

For standalone hibernate its easy to do, when you create the persistence object you can pass it a hash-table of key-value pairs. In your case the key "hibernate.hbm2dll.auto" and value of "validate"...

private Map properties = Util.newMap();

public EntityManagerFactory getEntityManagerFactory() {
    if (emf == null || !emf.isOpen()) {
        emf = Persistence.createEntityManagerFactory(PU, properties);
    }
    return emf;
}

public EntityManager getEntityManager() {
    if (em == null || !em.isOpen()) {
        em = getEntityManagerFactory().createEntityManager();
    }
    return em;
}

I then would have my configuration class populate the Map with things from my custom configuration file.

I don't believe you can modify an already open EntityManager instance. And though you can pass the EntityManager a Map, I found that it ignored those properties and only paid attention when you did it from the Factory...

Petriborg 2010-01-19 14:38:32

Yes - in a non-managed environment you can do this. But how do you do it in a managed environment (e.g. JBOSS) when the EntityManager is obtained like so: @PersistenceContext private EntityManager em;

Conor 2010-01-19 14:40:43

@conor Ah ok that makes sense... is the EM connection already opened for you?

Petriborg 2010-01-19 14:52:49

Yes - it's injected by JBoss.

Conor 2010-01-19 15:01:46

@conor ah then I'm not sure how you could do that, maybe somehow through JBoss? I don't use JBoss myself - our hibernate database application is standalone.

Petriborg 2010-01-19 15:06:39

Answer 2

A:

For JBoss 5.1 the following file needs to be edited:

<jboss_dir>/server/default/deployers/ejb3.deployer/META-INF/jpa-deployers-jboss-beans.xml

<bean name="PersistenceUnitDeployer" class="org.jboss.jpa.deployers.PersistenceUnitDeployer">
      <property name="defaultPersistenceProperties">
         <map keyClass="java.lang.String" valueClass="java.lang.String">
            <entry>
               <key>hibernate.transaction.manager_lookup_class</key>
               <value>org.hibernate.transaction.JBossTransactionManagerLookup</value>
            </entry>                
            <entry>
               <key>hibernate.hbm2ddl.auto</key>
               <value>validate</value>
            </entry>
            <entry>
               <key>hibernate.cache.provider_class</key>
               <value>org.hibernate.cache.HashtableCacheProvider</value>
            </entry>                
            <entry>
               <key>hibernate.jndi.java.naming.factory.initial</key>
               <value>org.jnp.interfaces.NamingContextFactory</value>
            </entry>
            <entry>
               <key>hibernate.jndi.java.naming.factory.url.pkgs</key>
               <value>org.jboss.naming:org.jnp.interfaces</value>
            </entry>
            <entry>
               <key>hibernate.bytecode.use_reflection_optimizer</key>
               <value>false</value>
            </entry>
            <!-- I don't think this is honored, but EJB3Deployer uses it -->
            <entry>
               <key>hibernate.bytecode.provider</key>
               <value>javassist</value>
            </entry>
         </map>
      </property>
</bean>

These properties can be edited in the following file in JBoss 4.2:

<jboss_dir>/server/default/deploy/ejb3.deployer/META-INF/persistence.properties

mtpettyp 2010-01-19 16:58:15

Great - thanks - I will try this.

Conor 2010-01-21 14:46:12

Ok - that works. To clarify: persistence.xml in jars/wars/ear override this file. So you need to update persistence.xml files so that they do not contain the (e.g.) hibernate.hbm2ddl.auto property.

Conor 2010-01-21 16:41:19

Yes, I find it good practice to never set those properties in the persistence.xml unless they are the same for development and production.

mtpettyp 2010-01-21 16:45:49

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Is it possible to override persistence.xml properties via configuration ?

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