问题
I have a java-ee web application that uses a persistence unit that is packaged as a jar dependency (Entity classes, EJB repositories, persistence.xml).
In order to get some acceptance tests running for the web application i need to override a property in the packaged persistence.xml. To be specific i need to disable the by default active eclipselink shared object cache by setting the following property.
<property name="eclipselink.cache.shared.default" value="false"/>
This is necessary because the acceptance tests are directly prepare/cleanup the database with dbunit. These modifications will put the eclipselink cache in a stale state (because the persistence unit is not involved in these modifications).
Is there a way in java-ee (or glassfish specific) to override properties in a persistence.xml that is located in a jar (starting from the web application war file, that is deployed when running my tests)?
There may be other ways, for example building the jar dependency specific for a test deployment, but this route seems complicated to me for only override one property in my persistence.xml.
回答1:
You can pass a properties map to Persistence.createEntityManagerFactory(). To do this you must manage your persistence context yourself (will not be able to inject it).
Another option is to set the property as a Java system property (-D=), this will not override an existing property in the persistence.xml, but with work if the property is not in the persistence.xml.
Another option is to put a SessionCustomizer or a SessionTuner in your persistence.xml to allow your own code to modify the configuration at runtime.
来源：https://stackoverflow.com/questions/17587414/it-is-possible-to-override-properties-in-a-persistence-xml-that-is-located-in-a