Hibernate 4在抽象工厂中创建会话工厂

Question

我在一个带有Hibernate 4.2的web应用程序中工作，我已经实现了抽象工厂模式，但是对于创建会话工厂，我没有init方法，因为我使用第一个调用来创建会话工厂，以便像静态一样向前重用，就像您可以看到我从DAOImpl获得了会话，并最终关闭了它。首先，我想问一下，这种做法是否正确？还有更好的练习吗？

public class HibernateSessionFactory {

    private static SessionFactory sessionFactory = buildSessionFactory();

    private static final Logger logger = LogManager.getLogger(HibernateSessionFactory.class);

    private static SessionFactory buildSessionFactory() {
        try {

            Configuration configuration = new Configuration();
            configuration.configure("hibernate.cfg.xml");

            ServiceRegistry sr = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry();
            SessionFactory sf = configuration.buildSessionFactory(sr);

            return sf;

        } catch (Exception ex) {
            logger.error("Initial SessionFactory creation failed.", ex);
            ex.printStackTrace();
            throw  ex;

        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void shutdownSessionFactory() {
        sessionFactory.close();
    }

}

DAOIMPL

public class RecordDAOImpl implements RecordDAO{.....

public String getRecord (Long id){
        Session session = HibernateSessionFactory.getSessionFactory().openSession();


        try {
            session.beginTransaction();     
            .
            .
            .

            session.getTransaction().commit();

        } catch (Exception e) {
            session.getTransaction().rollback();
        } finally {
            session.close();
        }

        return value;
    }

DAO

    public interface FieldDAO {.....

String getRecord (Long id);

工厂

public class HibernateFactoryDao extends DAOFactory {...

@Override
    public RecordDAOImpl getRecordDAO() {
        return new RecordDAOImpl();
    }

Answer 1

作为另一种选择，您可以使用CDI将工厂注入RecordDAOImpl，并根据ORM类型检索会话。

作为一个可能的例子，您可以尝试以下方法：

1.在您的ORM工厂之间创建一个指针限定符

@Qualifier
@Retention(RUNTIME)
@Target({ TYPE, METHOD, FIELD, PARAMETER })
public @interface ORMSessionFactory {

    ORMType value();

    public enum ORMType {
        HIBERNATE,
        ECLIPSELINK;
    }
}

2.为会话工厂定义接口。

public interface MySessionFactory {

    public SessionFactory getSessionFactory();

    public void shutdownSessionFactory();
}

如果有必要，3.创建一个包含所有ORM工厂实现的公共行为的抽象类。

public abstract class AbstractSessionFactory implements MySessionFactory {

    protected SessionFactory sessionFactory;

    public AbstractSessionFactory() {
        buildSessionFactory();
    }

    @Override
    public SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    @Override
    public void shutdownSessionFactory() {
        if (sessionFactory != null) {
            sessionFactory.close();
        }
    }

    protected abstract SessionFactory buildSessionFactory();
}

4.用相应的类型注释ORM工厂实现

@ORMSessionFactory(ORMType.HIBERNATE)
public class HibernateSessionFactory extends AbstractSessionFactory {

    @Override
    protected SessionFactory buildSessionFactory() {
        try {

            Configuration configuration = new Configuration();
            configuration.configure("hibernate.cfg.xml");

            ServiceRegistry sr = new StandardServiceRegistryBuilder()
                .applySettings(configuration.getProperties()).build();
            sessionFactory = configuration.buildSessionFactory(sr);

            return sessionFactory;

        } catch (Exception ex) {
            throw ex;
        }
    }
}

然后，在5.上，您可以在RecordDAOImpl上执行以下操作

public class RecordDAOImpl implements RecordDAO {

    @Inject
    @ORMSessionFactory(ORMType.HIBERNATE)
    private MySessionFactory mySessionFactory;

    @Override
    public String getRecord(Long id) {
        String value = null;
        Session session = mySessionFactory.getSessionFactory().openSession();

        try {
            session.beginTransaction();

            // do some transactional stuff

            session.getTransaction().commit();

        } catch (Exception e) {
            session.getTransaction().rollback();
        } finally {
            session.close();
        }

        return value;
    }
}

不要忘记，为了启用CDI，您应该在META (JAR)或WEB文件夹(WAR)中包含一个beans.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
                           http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
version="1.1" bean-discovery-mode="all">
</beans>