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

JBOSS 5.1 / EJB 3 / JPA / MySQL

For development we specify "hibernate.hbm2ddl.auto" as "update". This is done in several persistence.xml files embedded in several jars in an 开发者_StackOverflow中文版ear.

For production we'd like to override this to specify "validate".

Can this be done via configuration external to the ear?

(I know it's possible to do this in code in a non-managed environment)

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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

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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...

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For Wildfly, I would recommend for your persistence.xml to not have the hibernate.hbm2ddl.auto property at all.

Instead, in your launcher configuration for development where the VM arguments are being passed, add -Dhibernate.hbm2ddl.auto=update to the list.

You can have -Dhibernate.hbm2ddl.auto=validate for your production environments as well, but at least this keeps the changes outside of your application.