具有EclipseLink更新实体的Java SE JPA

Question

I am wondering if there is a better way to update entities after they have been read from the database.

This seems like too much code to do a simple task. I have tried using em.merge() which did not persists the data to the database.

public class PodcastManager {

    private EntityManagerFactory emf;


    public PodcastManager(EntityManagerFactory emf) {
        this.emf = emf;
    }

    public void updatePodcast(Podcast podcast) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        Podcast ptu = em.find(Podcast.class, podcast.getId());
        if ( ptu != null) {
            ptu.setTitle(podcast.getTitle());
            ptu.setDescription(podcast.getDescription());
            ptu.setUrl(podcast.getUrl());
            ptu.setLang(podcast.getLang());
            ptu.setCopyright(podcast.getCopyright());
            ptu.setItunesSubtitle(podcast.getItunesSubtitle());
            ptu.setItunesAuthor(podcast.getItunesAuthor());
            ptu.setItunesSummary(podcast.getItunesSummary());
            ptu.setItunesOwnerName(podcast.getItunesOwnerName());
            ptu.setItunesOwnerEmail(podcast.getItunesOwnerEmail());
            ptu.setItunesImageHREF(podcast.getItunesImageHREF());
            ptu.setExplicit(podcast.isExplicit());
        }
        em.getTransaction().commit();
        em.close();
    }
}

Answer 1

I managed to get it merge to work as follows.

public void updatePodcast(Podcast podcast) {
        EntityManager em = emf.createEntityManager();
        try {
            em.getTransaction().begin();
            em.merge(podcast);
            em.flush();

        } finally {
            em.getTransaction().commit();
            em.close();
        }
    }