Parameter value [multiVLANSupport] did not match expected type [java.util.List (n/a)] - spring-boot

Question

I have created an entity class that has a column which uses Attribute Converter of JPA:
#Convert(converter = StringListConverter.class)
private List<String> functionSpecificationLabel;
The converter class is :
#Converter
public class StringListConverter implements AttributeConverter<List<String>, String> {
#Override
public String convertToDatabaseColumn(List<String> list) {
return String.join(",", list);
}
#Override
public List<String> convertToEntityAttribute(String joined) {
return new ArrayList<>(Arrays.asList(joined.split(",")));
}
}
The expected values of the column in the Tables are like
functionSpecificationLabel
multiVLANSupport,telepresence,csaid
Now I need to return the rows that have multiVLANSupport,telepresence,csaid as value in functionSpecificationLabel column.
My Query in the repository for the same is :
#Query("Select pd from ProductDetailsEntity pd where pd.functionSpecificationLabel in (:labels)")
Optional<ProductDetailsEntity> findByFunctionSpecificationLabel(#Param("labels") final List<String> labels);
Now I face the issue as :
Parameter value [multiVLANSupport] did not match expected type [java.util.List (n/a)]

Answer 1

I am not exactly sure if this is even possible, here is how i have implemented to store list of values in an entity class using #ElementCollection You can read more about it here https://thorben-janssen.com/hibernate-tips-query-elementcollection/
A good discussion can be found here How to persist a property of type List<String> in JPA?. My suggestion is to avoid storing any values in db based on a delimiter.
Ideally, when storing such labels it is better to map them using OneToMany relationship. Also note that this will create an additional table in this case animal_labels.
Answer 1
Repository
#Repository
public interface AnimalRepository extends JpaRepository<Animal, UUID> {
List<Animal> findDistinctAnimalsByLabelsIsIn(List<String> cute);
}
Entity class
#Entity
#Table(name = "animal")
public class Animal {
#Id
#GeneratedValue
#Type(type = "uuid-char")
private UUID id;
private String name;
#ElementCollection(targetClass = String.class)
private List<String> labels;
public Animal() {
}
public Animal(String name, List<String> labels) {
this.name = name;
this.labels = labels;
}
public UUID getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<String> getLabels() {
return labels;
}
public void setLabels(List<String> labels) {
this.labels = labels;
}
}
Test:
#ExtendWith(SpringExtension.class)
#Transactional
#SpringBootTest(classes = TestApplication.class)
class CustomConverterTest {
#Autowired
private EntityManager entityManager;
#Autowired
private AnimalRepository animalRepository;
#Test
void customLabelConverter() {
Animal puppy = new Animal("Puppy", Arrays.asList("cute", "intelligent", "spy"));
Animal meow = new Animal("Cat", Arrays.asList("cute", "intelligent"));
entityManager.persist(puppy);
entityManager.persist(meow);
List<Animal> animalWithCutelabels = animalRepository.findDistinctAnimalsByLabelsIsIn(Arrays.asList("cute"));
List<Animal> animalWithSpylabels = animalRepository.findDistinctAnimalsByLabelsIsIn(Arrays.asList("spy"));
List<Animal> animalWithCuteAndSpylabels = animalRepository.findDistinctAnimalsByLabelsIsIn(Arrays.asList("cute", "spy"));
Assertions.assertEquals(2, animalWithCutelabels.size());
Assertions.assertEquals(1, animalWithSpylabels.size());
Assertions.assertEquals(2, animalWithCuteAndSpylabels.size());
}
}
Answer 2
If you do have any choice but to only go with the comma separated values then please find answer below for this approach:
Repository(since this is a string we cannot use list like in)
#Repository
public interface AnimalRepository extends JpaRepository<Animal, UUID> {
// Also note that the query goes as string and not list
List<Animal> findAllByLabelsContaining(String labels);
}
Test:
#Test
void customLabelConverter() {
Animal puppy = new Animal("Puppy", String.join(",", Arrays.asList("cute", "intelligent", "spy")));
Animal meow = new Animal("Cat", String.join(",", Arrays.asList("cute", "intelligent")));
entityManager.persist(puppy);
entityManager.persist(meow);
List<Animal> animalWithCutelabels = animalRepository.findAllByLabelsContaining(String.join(",", Arrays.asList("cute")));
List<Animal> animalWithSpylabels = animalRepository.findAllByLabelsContaining(String.join(",", Arrays.asList("spy")));
Assertions.assertEquals(2, animalWithCutelabels.size());
Assertions.assertEquals(1, animalWithSpylabels.size());
}
Entity:
#Entity
#Table(name = "animal")
public class Animal {
#Id
#GeneratedValue
#Type(type = "uuid-char")
private UUID id;
#Column
private String name;
#Column
private String labels;
public Animal() {
}
public Animal(String name, String labels) {
this.name = name;
this.labels = labels;
}
public UUID getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<String> getLabels() {
if (StringUtils.isEmpty(labels)) return Collections.emptyList();
return new ArrayList<>(Arrays.asList(labels.split(AnimalLabelsConverter.DELIMITER_COMMA)));
}
public void setLabels(List<String> labels) {
if (CollectionUtils.isEmpty(labels)) {
this.labels = "";
} else {
this.labels = String.join(AnimalLabelsConverter.DELIMITER_COMMA, labels);
}
}
#Converter
public static class AnimalLabelsConverter implements AttributeConverter<List<String>, String> {
private static final String DELIMITER_COMMA = ",";
#Override
public String convertToDatabaseColumn(List<String> labels) {
if (CollectionUtils.isEmpty(labels)) return "";
return String.join(DELIMITER_COMMA, labels);
}
#Override
public List<String> convertToEntityAttribute(String dbData) {
if (StringUtils.isEmpty(dbData)) return Collections.emptyList();
return new ArrayList<>(Arrays.asList(dbData.split(DELIMITER_COMMA)));
}
}
}