NamedQuery and no entity mapping - spring-boot

Question

I would like to achieve the following. I have a query and I would like to run it and return rows in a REST call.
I do not want to map the query to a physical table, how would I achieve this?
I use Spring Boot 1.5.2.

Answer 1

After some try and fixes, I got the following solution.
Create a POJO class, no #Entity annotation. You want to add packageScan instructions if it is not found.
public class ActivityReport1 {
#Column
private BigInteger id;
#Column
private String title;
//Only getters
public ActivityReport1(BigInteger id,
String title){
this.id = id;
this.title = title;
}
In a class which is annotated with #Entity create the resultset mapping
#SqlResultSetMappings({
#SqlResultSetMapping(name = "ActivityReport1Mapping",
classes = {
#ConstructorResult(targetClass = ActivityReport1.class, columns = {
#ColumnResult(name = "id"),
#ColumnResult(name = "title")
})
})
})
Add repository class
#Repository
#Transactional
public class IActivityReport1Repository {
#PersistenceContext
private EntityManager entityManager;
public List<ActivityReport1> getResults(String userLogin) {
Query query = entityManager.createNativeQuery(
"SELECT " +
"t.request_id as id, t.request_title as title " +
"FROM some_table t ", "ActivityReport1Mapping");
List<ActivityReport1> results = query.getResultList();
return results;
}
}
And finally, the service impl class.
#Service
#Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public class ActivityReport1ServiceImpl implements IActivityReport1Service {
private static final Logger _Logger = LoggerFactory.getLogger(ActivityReport1ServiceImpl.class);
#Autowired
private IActivityReport1Repository sessionFactory;
#Override
public List<ActivityReport1> runReport(String userLogin) {
List<ActivityReport1> reportRows = sessionFactory.getResults(userLogin);
return reportRows;
}
}
If you face with "Could not locate appropriate constructor", this means that on Java side it could not map db types to java types.
In my case I had to change id from Long to BigInteger and Timestamp to java.util.date.