我用过PreInsertEventListener
and PreUpdateEventListener
用于在表中插入创建日期和更新日期的事件侦听器。
我面临的问题是,当我将实体保存在数据库中时,创建日期无法插入表中,与更新记录时插入更新日期相同,它也不会插入更新日期。
我的代码示例如下所示:
听众类别:
public class PreInsertListener implements PreInsertEventListener,
PreUpdateEventListener
{
@Override
public boolean onPreInsert(PreInsertEvent arg0) {
City.class.cast(arg0.getEntity()).setCreated_date(new Date());
return false;
}
@Override
public boolean onPreUpdate(PreUpdateEvent arg0) {
System.out.println("Update event......");
City.class.cast(arg0.getEntity()).setUpdated_date(new Date());
return false;
}
}
Hibernate连接类:
public class HibernateUtil
{
private static final SessionFactory sessionFactory;
static {
try {
AnnotationConfiguration config = new AnnotationConfiguration();
config.setListener("pre-insert", new PreInsertListener());
config.setListener("pre-update", new PreInsertListener());
sessionFactory = config.configure().buildSessionFactory();;
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
DAO 中的实体保存和更新方法:
public Long saveCity(String cityName)
{
Session session = HibernateUtil.getSessionFactory().openSession();
Transaction transaction = null;
Long cityId = null;
try {
transaction = session.beginTransaction();
City city = new City();
city.setName(cityName);
cityId = (Long) session.save(city);
//session.flush();
transaction.commit();
} catch (HibernateException e) {
transaction.rollback();
e.printStackTrace();
} finally {
session.close();
}
return cityId;
}
public void updateCity(Long cityId, String cityName)
{
Session session = HibernateUtil.getSessionFactory().openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
City city = (City) session.get(City.class, cityId);
city.setName(cityName);
session.update(city);
//session.flush();
transaction.commit();
} catch (HibernateException e) {
transaction.rollback();
e.printStackTrace();
} finally {
session.close();
}
}
我的测试班:
public class Main
{
public static void main(String[] args) {
CityDAO cityDAO = new CityDAO();
long cityId1 = cityDAO.saveCity("New York");
cityDAO.updateCity(cityId1, "Paris");
}
}
如果我用过session.flush()
比它会插入创建和更新的日期,但每次我调用刷新方法时都会执行更新的查询。目前我评论了要调用的代码session.flush()
方法如代码所示。
这个问题的解决办法是什么?