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方法说明
| 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 |
2，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(); }
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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;------------------------------------------------------------------------------------
上面增加OR条件较为麻烦
可以用如下方法处理:
DetachedCriteria dc = DetachedCriteria.forClass(AClass.class);
Disjunction disjunction = Restrictions.disjunction(); if (key != null) { for (int i = 0; i < key.length; i++) { disjunction.add(Restrictions.like("col1", key[i], MatchMode.ANYWHERE)); } dc.add(disjunction); }