jar文件中EntityManagerFactory的Persistence.xml文件

Question

Is there any way to put content of persistence.xml file to the source code that calling EntityManagerFactory? I tried building a project that contain persistence.xml but when I call the it from another project I always get this error:

[PersistenceException: No Persistence provider for EntityManager named cassandra_pu]

I also extract the jar file to check whether the xml file is included or not, it;s included in the WEB-INF folder. To me it's really weird because the persistence.xml is already in the jar file, why it keeps asking for the xml file?

Answer 1

The persistence.xml file must be in the root of your classpath. WEB-INF is not in the root of the class-path. If you want to put it in a .jar file, place it in WEB-INF/lib, if you want to have it outside a .jar file, place it in WEB-INF/classes. If you use JPA2 you no longer need that file.