#201 - Added example for constructor expression in JPA projections.

jpa/example/src/main/java/example/springdata/jpa/projections/CustomerRepository.java

@@ -95,4 +95,13 @@ public interface CustomerRepository extends CrudRepository<Customer, Long> {
 	 * @return
 	 */
 	Page<CustomerProjection> findPagedProjectedBy(Pageable pageable);
+
+	/**
+	 * A DTO projection using a constructor expression in a manually declared query.
+	 * 
+	 * @param firstname
+	 * @return
+	 */
+	@Query("select new example.springdata.jpa.projections.CustomerDto(c.firstname) from Customer c where c.firstname = ?1")
+	Collection<CustomerDto> findDtoWithConstructorExpression(String firstname);
 }

jpa/example/src/test/java/example/springdata/jpa/projections/CustomerRepositoryIntegrationTest.java

@@ -117,6 +117,15 @@ public class CustomerRepositoryIntegrationTest {
 		assertThat(((TargetAware) projectedDave).getTarget(), is(instanceOf(Map.class)));
 	}
 
+	@Test
+	public void projectsDtoUsingConstructorExpression() {
+
+		Collection<CustomerDto> result = customers.findDtoWithConstructorExpression("Dave");
+
+		assertThat(result, hasSize(1));
+		assertThat(result.iterator().next().getFirstname(), is("Dave"));
+	}
+
 	@Test
 	public void supportsProjectionInCombinationWithPagination() {