Hibernate Criteria 的用法

Hibernate Criteria 的用法 1. 普通的查询 Criteria criteria = session.createCriteria(Track.class); criteria.add(Restrictions.le(”playTime”,length)); return criteria.list(); 2. 其他 Criteria criteria = session.createCriteria(Track.class); criteria.add(Restrictions.le(”playTime”,length)); criteria.addOrder(Order.asc(”title”).ignoreCase()); return criteria.list(); 3. 组合条件查询 Criteria critera = session.createCriteria(Track.class); criteria.add(Restrictions.le(”playTime”,length)); criteria.add(Restrictions.like(”title”,length)); criteria.addOrder(Order.asc(”title”).ignoreCase()); 4. 宽松条件查询(OR) session.createCriteria(Tarck.class) .add(Restrictions.disjunction() .add(Restrictions.le(”playTime”),length)) .add(Restrictions.like(”title”), “%A%”))) .addOrder(Order.asc(”title”).ignoreCase()) .list(); 5.对单一属性做简单投影，返回的List 是String类型的List对象 Session.createCriteria(Track.class) .add(Resritctions.like(”title”,”sometext”, MatchMOde.ANYWHERE).ignoreCase()) .setProjection(Projections.property(”title”)) .list(); 6.对多个属性做投影，返回Object数组类型的List对象 Session.createCriteria(Track.class) .add(Resritctions.like(”title”,”sometext”, MatchMOde.ANYWHERE).ignoreCase()) .setProjection(Projections.property(”title”)) .setProjection(Projections.property(”playTime”)) .list(); 7.带聚合的投影 a.创业一个ProjectionList实例 b.对sourceMedia字段分组 c.返回记录总数 d.返回分组的结果集中playTime的最大值 Session.createCriteria(Track.class) .setProjection(Projections.projectionList()) //a .add(Projections.groupProperty(”sourceMedia”)) //b .add(Projections.rowCount()) //c .add(Projections.max(”playTime”))); //d //select count(*), max(track.playTime) from track group by track.sourceMedia 8. 对聚合投影结果排序要通过设置别名来完成 Session.createCriteria(Track.class) .setProjection(Projections.projectionList()) .add(Projections.groupProperty(”sourceMedia”).as(”media”)) .add(Projections.rowCount()) .add(Projections.max(”playTime”))); .addOrder(Order.asc(”media”)); 9. 在关联中应用条件查询 Criteria criteria = session.createCriteria(Track.class); Criteria artistCriteria = criteria.createCriteria(”artists”); artistCritera.add(Restrictions.like(”name”,namePattern)); artisCriteria.addOrder(Order.asc(”name”).ignoreCase()); criteria.list(); 10. 示例查询 a.示例查询中，值为null的忽略 b.对字符串值按照区分大小写的逐字比较 c.如果比较时，需要忽略为0的属性，可以调用example.excludeZeroes() d.如果希望对值为null的属性进行匹配可以调用example.excludeNone() e.example.excludeProperty()用来明确忽略指定名称的特定属性 f.调整字符串处理，还可以使用ignoreCase()和enableLike()方法 SourceMedia media = new SourceMedia(); media.setName(”example”) Track track = new Track(); track.setSourceMedia(media); \\media 是一个SourceMedia对象 Example example = Example.create(track); Criteria criteria = session.createCriteria(Track.class); criteria.add(example); criteria.addOrder(Order.asc(”title”)); return critera.list();