方法 |
说明 |
Restrictions .eq |
= |
Restrictions .allEq |
利用Map来进行多个等于的限制 |
Restrictions .gt |
> |
Restrictions .ge |
>= |
Restrictions .lt |
< |
Restrictions .le |
<= |
Restrictions .between |
BETWEEN |
Restrictions .like |
LIKE |
Restrictions .in |
in |
Restrictions .and |
and |
Restrictions .or |
or |
Restrictions .sqlRestriction |
用SQL限定查询 |
QBC常用限定方法
Restrictions .eq --> equal,等于.
Restrictions .allEq --> 参数为Map对象,使用key/value进行多个等于的比对,相当于多个Restrictions .eq 的效果
Restrictions .gt --> great-than > 大于
Restrictions .ge --> great-equal >= 大于等于
Restrictions .lt --> less-than, < 小于
Restrictions .le --> less-equal <= 小于等于
Restrictions .between --> 对应SQL的between子句
Restrictions .like --> 对应SQL的LIKE子句
Restrictions .in --> 对应SQL的in子句
Restrictions .and --> and 关系
Restrictions .or --> or 关系
Restrictions .isNull --> 判断属性是否为空,为空则返回true
Restrictions .isNotNull --> 与isNull相反
Restrictions .sqlRestriction --> SQL限定的查询
Order.asc --> 根据传入的字段进行升序排序
Order.desc --> 根据传入的字段进行降序排序
MatchMode.EXACT --> 字符串精确匹配.相当于"like 'value'"
MatchMode.ANYWHERE --> 字符串在中间匹配.相当于"like '%value%'"
MatchMode.START --> 字符串在最前面的位置.相当于"like 'value%'"
MatchMode.END --> 字符串在最后面的位置.相当于"like '%value'"
例子
查询年龄在20-30岁之间的所有学生对象
List list = session.createCriteria(Student.class)
.add(Restrictions .between("age",new Integer(20),new Integer(30)).list();
查询学生姓名在AAA,BBB,CCC之间的学生对象
String[] names = {"AAA","BBB","CCC"};
List list = session.createCriteria(Student.class)
.add(Restrictions .in("name",names)).list();
查询年龄为空的学生对象
List list = session.createCriteria(Student.class)
.add(Restrictions .isNull("age")).list();
查询年龄等于20或者年龄为空的学生对象
List list = session.createCriteria(Student.class)
.add(Restrictions .or(Restrictions .eq("age",new Integer(20)),
Restrictions .isNull("age")).list();
--------------------------------------------------------------------
使用QBC实现动态查询
public List findStudents(String name,int age){
Criteria criteria = session.createCriteria(Student.class);
if(name != null){
criteria.add(Restrictions .liek("name",name,MatchMode.ANYWHERE));
}
if(age != 0){
criteria.add(Restrictions .eq("age",new Integer(age)));
}
criteria.addOrder(Order.asc("name"));//根据名字升序排列
return criteria.list();
}
-----------------------------------------------------------------------------------
今天用了写hibernate 高级查询时用了Restrictions (当然Expression也是可以以的)这个类.感觉不错.
下面的代码写的不易读.其实核心就是一句
Restrictions .or(Restrictions .like(),Restrictions .or(Restrictions .like,........))
里面的or可以无限加的.还是比较好用
Session session = getHibernateTemplate().getSessionFactory()
.openSession();
Criteria criteria = session.createCriteria(Film.class);
List<Film> list = criteria.add(
Restrictions .or(Restrictions .like("description", key,MatchMode.ANYWHERE),
Restrictions .or(Restrictions .like("name", key,MatchMode.ANYWHERE),
Restrictions .or( Restrictions .like("direct", key,MatchMode.ANYWHERE),
Restrictions .or(Restrictions .like("mainplay",key,MatchMode.ANYWHERE),
Restrictions .like("filearea", key,MatchMode.ANYWHERE)))))).list();
session.close();
return list;