Hibernate-查询

 ???????/** ????????* ?一、Session查询 ????????* ??get()在无主键的情况下返回null ????????* ??load()在无主键的情况下会产生异常 ????????**/
 ?????????HibernateSessionFactory.getSession().get(Member.class, "id-a"); ?????????HibernateSessionFactory.getSession().load(Member.class, "id-b");

 ????????二、Query查询 
 ????????//Member是pojo类的名称 ??????????String hql="from Member as a"; ?// 返回类型:List<Member> ?????????String hql="select a.mid from Member as a";//返回类型:List<String> ???????????????String hql="select a.mid,a.name,a.sex from Member as a";//返回类型:List<Object[]> ???????????????????//将查询后的结果转换为指定的vo类型,是根据查询返回列的名称自动匹配的 ?????????query.setResultTransformer(new AliasToBeanResultTransformer(Member.class)); ???????????????????????????/** ??????????* 限定查询 ??????????*/ ?????????String kw="hello"; ?????????String hql="from Member as a where a.age=? and a.mid like ?"; ?????????Query query = HibernateSessionFactory.getSession().createQuery(hql); ?????????//设值 (索引从0开始) ?????????query.setParameter(0, 10); ?????????query.setParameter(1, "%"+kw+"%"); ?????????List list = query.list(); ???????????????????/** ??????????* 统计查询 ??????????*/ ?????????String kw="hello"; ?????????String hql="select count(*) from Member as a where a.age=? and a.mid like ?"; ?????????Query query = HibernateSessionFactory.getSession().createQuery(hql); ?????????//设值 (索引从0开始) ?????????query.setParameter(0, 10); ?????????query.setParameter(1, "%"+kw+"%"); ?????????Object obj = query.uniqueResult(); ?????????????????????????/** ??????????* 分页查询 ??????????*/ ?????????int currentPage=1; ?????????int lineSize=2; ?????????String hql="from Member as a"; ?????????Query query = HibernateSessionFactory.getSession().createQuery(hql); ?????????query.setFirstResult((currentPage-1)*lineSize); ?????????query.setMaxResults(lineSize); ?????????List list = query.list(); ???????????????????/** ??????????* 分组查询 ??????????*/ ?????????String hql="select a.sex, count(*) from Member as a where a.age=? ?group by a.sex"; ?????????Query query = HibernateSessionFactory.getSession().createQuery(hql); ?????????//设值 (索引从0开始) ?????????query.setParameter(0, 10); ?????????List list = query.list();