Hibernate Group by Criteria Object

Please refer to this for the example .The main point is to use the groupProperty() , and the related aggregate functions provided by the Projections class.

For example :

SELECT column_name, max(column_name) , min (column_name) , count(column_name)FROM table_nameWHERE column_name > xxxxxGROUP BY column_name

Its equivalent criteria object is :

List result = session.createCriteria(SomeTable.class)                           .add(Restrictions.ge("someColumn", xxxxx))                          .setProjection(Projections.projectionList()                            .add(Projections.groupProperty("someColumn"))                            .add(Projections.max("someColumn"))                            .add(Projections.min("someColumn"))                            .add(Projections.count("someColumn"))                               ).list();

GroupBy using in Hibernate

This is the resulting code

public Map getStateCounts(final Collection ids) {    HibernateSession hibernateSession = new HibernateSession();    Session session = hibernateSession.getSession();    Criteria criteria = session.createCriteria(DownloadRequestEntity.class)            .add(Restrictions.in("id", ids));    ProjectionList projectionList = Projections.projectionList();    projectionList.add(Projections.groupProperty("state"));    projectionList.add(Projections.rowCount());    criteria.setProjection(projectionList);    List results = criteria.list();    Map stateMap = new HashMap();    for (Object[] obj : results) {        DownloadState downloadState = (DownloadState) obj[0];        stateMap.put(downloadState.getDescription().toLowerCase() (Integer) obj[1]);    }    hibernateSession.closeSession();    return stateMap;}

You can use the approach @Ken Chan mentions, and add a single line of code after that if you want a specific list of Objects, example:

    session.createCriteria(SomeTable.class)                           .add(Restrictions.ge("someColumn", xxxxx))                          .setProjection(Projections.projectionList()                            .add(Projections.groupProperty("someColumn"))                            .add(Projections.max("someColumn"))                            .add(Projections.min("someColumn"))                            .add(Projections.count("someColumn"))                               ).setResultTransformer(Transformers.aliasToBean(SomeClazz.class));List<SomeClazz> objectList = (List<SomeClazz>) criteria.list();