如何在Hibernate状态下进行乐观锁定

我使用了Hibernate批注，这是我的乐观锁定的实现

@Entitypublic class MyObject {    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    private Long id;    private String data;    @Version    private Integer version; // this is version field}

这是工作示例

// Entity class with version field@Entitypublic class Ent1 implements Serializable {    private static final long serialVersionUID = -5580880562659281420L;    @Id    Integer a1;    Integer a2;    @Version    private Integer version;}

以及一些向数据库添加一个元素的代码

        session = HibernateHelper.getSessionFactory().openSession();        transaction = session.beginTransaction();        Ent1 entity = new Ent1();        entity.setA1(new Integer(0));        entity.setA2(new Integer(1));        session.save(entity);        transaction.commit();        // get saved object and modify it        transaction = session.beginTransaction();        List<Ent1> list = (List<Ent1>)session.createQuery("FROM Ent1 WHERe a1 = 0").list();        Ent1 ent = list.get(0);        ent.setA2(new Integer(1000));        session.save(ent);        transaction.commit();

创建后，数据库中的新元素具有版本0。修改后-版本1。

HibernateHelper.java

import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;public class HibernateHelper {    private static final SessionFactory sessionFactory;    static {        try { sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();        } catch (Throwable ex) { System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex);        }    }    public static SessionFactory getSessionFactory() {        return sessionFactory;    }}