javaee 6 rest api named query result - jpa

Question

I have a simple JEE6 rest class that gets the data from db2. I am using Jackson in ApplicationConfig class to convert the entity objects to json. It converts with the field names as the key and the value as the right hand value. So for example:
Class Entity {
String name;
String address;
}
converts to
{name:"hello", address:"world"}
The service is as follows:
public List<T> findAll() {
javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
return getEntityManager().createQuery(cq).getResultList();
}
Now I want to only return the name in json format. So I created a named query as follows in the entity class:
#NamedQuery(name = "justGetName", query = "SELECT a.name FROM Applications a")
And the service changed to
public List<T> findAll() {
return getEntityManager().createNamedQuery("justGetName").getResultList();
}
This returns the following array:
[{"first","second","third"}]
But I want to get back:
[{name:"first",name:"second",name:"third"}]
How do I write the named query so that the class field names are added to the json structure? Thank you.

Answer 1

You querying a list of strings from your database and this is what the service returns.
Their are multiple ways to achieve your goal.
Pure JPA
Using #JsonIgnore to tell Jackson not to serialize an attribute
class Application {
String name;
#JsonIgnore
String address;
}
Create a new Entity class that only contains the attributes you would like to share
class ApplicationName {
String name;
}
Alternatively you could introduce a separate class that only contains the attributes you would like to share and convert the results from the query into this class and return than the list of this converted values.