Hibernate 4 在抽象工厂中创建sessionfactory

Question

我在使用 Hibernate 4.2 的网络应用程序中工作，我实现了抽象工厂模式，但是为了创建会话工厂，我没有 init 方法，因为我使用第一个调用来创建会话工厂以在像静态一样向前，就像你可以看到我从 DAOImpl 获得会话，开始工作，最后我关闭它。首先我想问一下这个做法对不对？还有其他更好的做法吗？

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

作为替代方案，您可以使用 CDI 将您的工厂注入 RecordDAOImpl 并根据您的 ORM 类型检索您的会话。

作为一个可能的例子，您可以尝试以下操作：

1. 创建限定符以在 ORM 工厂之间针刺

@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();
}

3. 如有必要，创建一个抽象 class 来保存所有 ORM 工厂实现中的通用行为

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. 用相应的类型注释您的 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;
        }
    }
}

5. 然后，在您的 RecordDAOImpl 上，您可以执行以下操作

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，您的 META-INF[=47= 中应该有一个 beans.xml ] (JAR) 或 WEB-INF 文件夹 (WAR):

<?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>

Hibernate 4 在抽象工厂中创建sessionfactory

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