Hibernate-Criteria Queries

1.实例

接口org.hibernate.Criteria针对特殊持久层类进行查询，Sesion是Criteria的工厂：

 Criteria crit = sess.createCriteria(Cat.class);
 crit.setMaxResults(50);
 List cats = crit.list();

2.精简结果集

 List cats = sess.createCriteria(Cat.class)
     .add( Restrictions.like("name", "Fritz%") )
     .add( Restrictions.between("weight", minWeight, maxWeight) )
     .list();

 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();

 List cats = sess.createCriteria(Cat.class)
     .add( Restrictions.sqlRestriction("lower({alias}.name) like lower(?)", "Fritz%", Hibernate.STRING) )
     .list();

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

3.结果集排序

 List cats = sess.createCriteria(Cat.class)
     .add( Restrictions.like("name", "F%")
     .addOrder( Order.asc("name") )
     .addOrder( Order.desc("age") )
     .setMaxResults(50)
     .list();

 List cats = sess.createCriteria(Cat.class)
     .add( Property.forName("name").like("F%") )
     .addOrder( Property.forName("name").asc() )
     .addOrder( Property.forName("age").desc() )
     .setMaxResults(50)
     .list();

4.关联

 List cats = sess.createCriteria(Cat.class)
     .add( Restrictions.like("name", "F%") )
     .createCriteria("kittens")
         .add( Restrictions.like("name", "F%") )
     .list();

 List cats = sess.createCriteria(Cat.class)
     .createAlias("kittens", "kt")
     .createAlias("mate", "mt")
     .add( Restrictions.eqProperty("kt.name", "mt.name") )
     .list();

 List cats = sess.createCriteria(Cat.class)
     .createCriteria("kittens", "kt")
         .add( Restrictions.eq("name", "F%") )
     .setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP)
     .list();
 Iterator iter = cats.iterator();
 while ( iter.hasNext() ) {
     Map map = (Map) iter.next();
     Cat cat = (Cat) map.get(Criteria.ROOT_ALIAS);
     Cat kitten = (Cat) map.get("kt");
 }

 List cats = session.createCriteria( Cat.class )
                        .createAlias("mate", "mt", Criteria.LEFT_JOIN, Restrictions.like("mt.name", "good%") )
                        .addOrder(Order.asc("mt.age"))
                        .list();
     

5.动态关联检索

List cats = sess.createCriteria(Cat.class)
    .add( Restrictions.like("name", "Fritz%") )
    .setFetchMode("mate", FetchMode.EAGER)
    .setFetchMode("kittens", FetchMode.EAGER)
    .list();

6.组件

Cat有fullName属性，fullName属性又有lastName属性：

List cats = session.createCriteria(Cat.class)
            .add(Restrictions.eq("fullName.lastName", "Cattington"))
            .list();