An attempt to use json/array types of hibernate-types in Spring Data projections
Projection:
public interface ParentProjection { String getName(); List<String> getChildNames(); }Query:
@Query(value = "" + "select " + " p.name as name, " + " array_agg(c.name) as childNames " + "from " + " parents p " + " join children c on c.parent_id = p.id " + "where " + " p.id = ?1 " + "group by " + " p.name" + "", nativeQuery = true) Optional<ParentProjection> getParentWithChildNamesAsArray(Integer id);public class PostgreSQLCustomDialect extends PostgreSQL95Dialect { public PostgreSQLCustomDialect() { super(); registerHibernateType(Types.OTHER, JsonNodeStringType.class.getName()); registerHibernateType(Types.ARRAY, StringArrayType.class.getName()); } }When PostgreSQL aggregate function array_agg is used in the query above, then the following exception is raised:
org.springframework.orm.jpa.JpaSystemException: Could not instantiate Type: com.vladmihalcea.hibernate.type.array.StringArrayType; If json_agg function is used, then we have another exception:
java.lang.IllegalArgumentException: Projection type must be an interface!