hibernate3 的常用操作（批量刪除，批量插入，關聯查詢）

1 批量刪除是調用sql引擎執行sql語句。批量插入有兩種方式，a：自己拼接出一條sql語句 b：利用hibernate的session一級緩存，每多少條刷新緩存存入數據庫

@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) { // 每一百條刷新并寫入數據庫
                    session.flush();
                    session.clear();
                }
            }
        } catch (HibernateException e) {
            e.printStackTrace();
        }finally{
            tx.commit();
            session.close();
        }
    }
}

}
//批量查詢，當然hibernate也提供了使用某一個屬性查詢出集合
    String hql = "from Goods  where  merchandiseId in (:ids)";
    List<Goods> goodsList = goodsDao.createQuery(hql).setParameterList("ids", idList).list();</pre> 


 2 批量插入采用sql時如下： 

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 關聯查詢:當沒有在實體中設置關聯關系，而是自己建立的中間表時，可以用hql關聯查詢數據。 

    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);
    }