hibernate Restrictions用法

[url]http://xuganggogo.iteye.com/blog/440078[/url]
QBC常用限定方法
[b]Restrictions.eq --> equal,等于.
Restrictions.ne --> 不等于
Restrictions.allEq --> 利用Map来进行多个等于的限制,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'"[/b]
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;

如果需要循环设置OR查询，可以用到disjunction，以下两段代码实现同样的功能。

List cats = sess.createCriteria(Cat.class)
    .add( Restrictions.like("name", "Fritz%") )
    .add( Restrictions.or(
        Restrictions.eq( "age", new Integer(0) ),
        Restrictions.isNull("age")
    ) )
    .list();

List cats = sess.createCriteria(Cat.class)
    .add( Restrictions.in( "name", new String[] { "Fritz", "Izi", "Pk" } ) )
    .add( Restrictions.disjunction()
        .add( Restrictions.isNull("age") )
        .add( Restrictions.eq("age", new Integer(0) ) )
        .add( Restrictions.eq("age", new Integer(1) ) )
        .add( Restrictions.eq("age", new Integer(2) ) )
    ) )
    .list();