hibernate3 的常用操作（批量删除，批量插入，关联查询）

1 批量删除是调用sql引擎执行sql语句。批量插入有两种方式，a：自己拼接出一条sql语句 b：利用hibernate的session一级缓存，每多少条刷新缓存存入数据库

@Component
public class StudentDao extends HibernateDao<Student, Integer> {

public void deleteByIds(List<?> ids) {
String hql = "delete from Student where id in (:ids)";
createQuery(hql).setParameterList("ids", ids).executeUpdate();
}

public void saveBatch(List<Student> stuList) {
if (null != stuList && stuList.size() > 0) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
try {
for (int i = 0; i < stuList.size(); i++) {
session.save(stuList.get(i));
if (i % 100 == 0) { // 每一百条刷新并写入数据库
session.flush();
session.clear();
}
}
} catch (HibernateException e) {
e.printStackTrace();
}finally{
tx.commit();
session.close();
}
}
}
}
//批量查询，当然hibernate也提供了使用某一个属性查询出集合
String hql = "from Goods  where  merchandiseId in (:ids)";
List<Goods> goodsList = goodsDao.createQuery(hql).setParameterList("ids", idList).list();

2 批量插入采用sql时如下：

public void setMappingGoods(Integer merchandiseId,List<Integer> ids) {
StringBuilder sb = new StringBuilder();
sb.append("insert into mapping_goods(kid,oid) values ");
for(Integer id:ids){
sb.append("("+merchandiseId+","+id+")"+",");
}
goodsmapDao.getSession().createSQLQuery(sb.substring(0, sb.length()-1)).executeUpdate();
}

3 hql 关联查询:当没有在实体中设置关联关系，而是自己建立的中间表时，可以用hql关联查询数据。

public List<Goods> getMappingGoods(String kuuid) {
if(StringUtils.empty(kuuid)){
return new ArrayList<Goods>();
}
String hql = " from Goods g where  g.merchandiseUuid!=? and ( (g.merchandiseUuid in (select mp.kuuid from Goodsmap mp where mp.kuuid=? or mp.ouuid=?)) or (g.merchandiseUuid in (select mp.ouuid from Goodsmap mp where mp.kuuid=? or mp.ouuid=?)))";
return goodsDao.find(hql,kuuid, kuuid,kuuid, kuuid,kuuid);
}