我编写了一个dao接口的基于休眠的实现,但是现在我意识到有很多重复的代码,例如打开sesison,开始事务,提交和回滚,每种方法都具有相同的代码,我想知道将其保存在一个地方的方式,听说过一个叫做AbstractDao的东西,但是这个概念在这里如何适用,真的有效,我想减少样板代码。
这是我的实现类的片段
package com.javarnd.cip.dao;
import java.util.ArrayList;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.javarnd.cip.db.HibernateUtil;
import com.javarnd.cip.model.Sports;
public class SportsDaoImpl implements SportsDao {
public void save(Sports sports) {
Session session = HibernateUtil.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
session.save(sports);
session.getTransaction().commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
e.printStackTrace();
} finally {
session.close();
}
}
public List<Sports> findAll() {
Session session = HibernateUtil.openSession();
Transaction tx = null;
List<Sports> sportsList = new ArrayList<>();
try {
tx = session.beginTransaction();
sportsList = session.createQuery("FROM Sports", Sports.class).list();
session.getTransaction().commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
return null;
}
e.printStackTrace();
} finally {
session.close();
}
return sportsList;
}
public void update(Sports sports) {
Session session = HibernateUtil.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
Sports sportsData = session.get(Sports.class, sports.getSportId());
sportsData.setName(sports.getName());
session.getTransaction().commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
e.printStackTrace();
} finally {
session.close();
}
}
public void delete(Sports sports) {
Session session = HibernateUtil.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
Sports sportsData = session.get(Sports.class, sports.getSportId());
session.delete(sportsData);
session.getTransaction().commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
e.printStackTrace();
} finally {
session.close();
}
}
@Override
public Sports findById(long sportsId) {
Session session = HibernateUtil.openSession();
Transaction tx = null;
Sports sportsData = null;
try {
tx = session.beginTransaction();
sportsData = session.get(Sports.class, sportsId);
session.getTransaction().commit();
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
e.printStackTrace();
} finally {
session.close();
}
return sportsData;
}
}
答案 0 :(得分:0)
如果您可以使用Java 8,它可能看起来像这样:
private static <OUTPUT> OUTPUT runInTransaction(Function<Session, OUTPUT> function) {
Transaction tx = null;
try (Session session = HibernateUtil.openSession()) {
tx = session.beginTransaction();
final OUTPUT result = function.apply(session);
session.getTransaction().commit();
return result;
} catch (Exception e) {
if (tx != null) {
tx.rollback();
}
e.printStackTrace();
return null;
}
}
然后:
runInTransaction(session -> {
return session.get(Sports.class, sportsId);
});