java - 方法 Hibernate.createBlob() 已从 Hibernate 4.0.1 弃用并移至 Hibernate.getLobCreator(Session session).createBlob()

Question

方法 Hibernate.createBlob() 已从 Hibernate 4.0.1 中弃用并移至 Hibernate.getLobCreator(Session session).createBlob()。我应该在方法 getLobCreator(Session session) 中传递什么的任何解决方案，即代替 Session，或显示如何使用 Spring 和 Hibernate 检索图像并将图像保存到 DB 中的任何其他解决方案。

Answer 1

根据 this easy tutorial ,

Session Object

A Session is used to get a physical connection with a database. The Session object is lightweight and designed to be instantiated each time an interaction is needed with the database. Persistent objects are saved and retrieved through a Session object.

The session objects should not be kept open for a long time because they are not usually thread safe and they should be created and destroyed them as needed.

在 Hibernate 4.0+ 中，您可以从 SessionFactory 中获取 Session 对象。让我们为此任务编写一个方便的类。

package your.company.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class HibernateUtil {

    private static final SessionFactory sessionFactory;
    static {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            Configuration configuration = new Configuration().configure();
            ServiceRegistry registry = new ServiceRegistryBuilder()
                    .applySettings(configuration.getProperties())
                    .buildServiceRegistry();
            sessionFactory = configuration.buildSessionFactory(registry);
        } catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void shutdown() {
        // Close caches and connection pools
        getSessionFactory().close();
    }

}

然后:

Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();

byte[] bFile = /* load image into byte array */;
Blob image = Hibernate.getLobCreator(session).createBlob(bFile);
/* ? Your actions with Blob ? */

session.getTransaction().commit();

如果可行，请告诉我。

或者(假设Employee是一个POJO，字段@Lob private byte[] photo;，绑定(bind)到对应的表):

Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();

byte[] bFile = /* load image into byte array */;
Employee employee = new Employee();
employee.setPhoto(bFile);

session.save(employee);

session.getTransaction().commit();

信息来自 mkyong.com .在这里您可以找到如何将图像保存到数据库中的完整示例。以及如何检索图像的示例。

---

注意:对于 Hibernate 4.3+，您在 try block 中的代码略有变化。因为类 ServiceRegistryBuilder 被替换为 StandardServiceRegistryBuilder。

Configuration configuration = new Configuration().configure();
StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder()
        .applySettings(configuration.getProperties());
SessionFactory factory = configuration.buildSessionFactory(builder.build());