APPENDIX A n MORE ADVANCED FEATURES 235 (Crystaltech web hosting) n
APPENDIX A n MORE ADVANCED FEATURES 235 n MORE ADVANCED FEATURES 235 Listings A-1 and A-2) containing the appropriate configuration information. From the EntityManagerFactory class, you can request EntityManager instances that are used to access the entities. You have probably already spotted that the EJB 3 Persistenceclass corresponds roughly to Configuration, that EntityManagerFactory is a dead ringer for SessionFactory, and that EntityManager is the analog of Session. The example code in Listing A-3 pushes this point home. The EntityManager instance is used in a very similar way to the Sessionclass shown throughout this book (although some of the method names are slightly different persist() in this example corresponds to Session s save() method). Listing A-3. Using EJB 3 Persistence in J2SE Code package com.hibernatebook.advanced; import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Ejb3Example { @SuppressWarnings(”unchecked”) public static void main(String[] args) { EntityManagerFactory factory = Persistence.createEntityManagerFactory(”sampleManager”); EntityManager manager = factory.createEntityManager(); manager.getTransaction().begin(); manager.persist(new Sample(”FAQ”)); manager.persist(new Sample(”RTFM”)); manager.persist(new Sample(”PDQ”)); manager.persist(new Sample(”ASAP”)); manager.getTransaction().commit(); Query query = manager.createQuery(”from Sample”); manager.getTransaction().begin(); List
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