如何在Java SE应用程序中使用JPA EntityManager

Question

I'm working on a java SE application and I want to use JPA EntityManager for managing database operations. From my searches, I found that there is need to make a persistence.xml file. But I don't know where should I put it. My search results say it should be place in the webRoot\\META-INF , but my project it's not a J2EE project, so it has not webRoot or META-INF directories. Here is my code for getting entity manager:

 private static EntityManagerFactory factory = Persistence.createEntityManagerFactory("unitName");
 protected EntityManager entityManager =  entityManager = factory.createEntityManager();

But this always causes javax.persistence.PersistenceException exception and return me this message:

No Persistence provider for EntityManager named unitName

How can I solve this problem?

Thank you for your attention.

Answer 1

First of all you can CREATE a file META-INF like that:

but if you are using Netbeans, so when you create Entity Classes From Database , that folder will be created automaticly, you can try that.

good luck.

Answer 2

Since you're using Hibernate, you can see its Tutorial Using the Java Persistence API (JPA) :

In Java™ SE environments the persistence provider (Hibernate in this case) is required to locate all JPA configuration files by classpath lookup of the META-INF/persistence.xml resource name.

Put the persistence.xml to

• ./src/main/resources/META-INF/persistence.xml if you use maven.
• ./src/META-INF/persistence.xml if you don't use maven.

Once done, the above tutorial also tells you how to configure the following and use JPA step by step. Check here if you need any persistence template.