How to use Hibernate to transform a query result to a Class instance

Problem

Your query returns an object which is a class , but for some reason you can’t use it as an entity

Solution:

The Class

public class MY_CLASS {   
  long a;   
  String b;   
}

In the Mapping file:

<sql-query name="source-settings-by-SOURCEID">   
<return-scalar type="long" column="a" />   
<return-scalar type="string" column="b" />   
<![CDATA[   
  SELECT   
    TableA.a_value as a,   
    TableB.b_value as b   
  FROM TableA, TableB   
  ]]>   
</sql-query>

In the call to the query:

Query query = session.getNamedQuery(QUERY_NAME);   
query.setParameter("PARAM", PARAM); //optional   
rval = query.setResultTransformer(Transformers.aliasToBean(MY_CLASS.class)).list();

Note:

• The whole point is to keep the column name exactly like the class field names , this is how the aliasToBean works.
• In the mapping file ,”long” ,”string” - are lower case on purpose , it failed when I used capitals. (Long, String)