Selecting fields on Spring Data

Question

I'm trying to find information about how to select only certain fields of an entity using Spring Data (I'm using JPA). I want to select only specific information of an entity, the repository interfaces gives you the ways to return the information of the WHOLE entity!. Some times I only need 2 or 3 fields of an entity and returning 20,30, ...100.. fields may be a little overkill.

This kind of functionality is something that I would do using Hibernate Criteria Projections, or even JPA "SELECT NEW ...." queries. Don't know if it is possible with Spring Data.

Thanks.

Answer 1

What you can do is return a List<Object[]> from repository. Then in your service class iterate over this list and manually create the object you need. Sample repository method

@Query("select el.moduleId, el.threadId from ExceptionLog el")
public List<Object[]> tempQuery();

Answer 2

I think you can also do it in this way

SomeDataPOJO{
    required col1
    required col2
}

and then write query like this

@Query("select new SomeDataPOJO from requiredTable where xyz="abc")
public List<SomeDataPoJO> tempQuery()