How to do a ManyToMany relationship insert - spring

Question

I am studying spring boot data using this API SWAPI, I did almost things but now I dont know how to map the relationship about two lists, above you can see my code and entities.
Entity Film
#Data
#Entity
public class Film extends Persistent<Long> {
private String title;
#JsonProperty(value = "episode_id")
private int episodeId;
#JsonProperty(value = "opening_crawl")
#Column(columnDefinition = "CLOB")
private String openingCrawl;
private String director;
private String producer;
#JsonDeserialize(converter = StringToLocalDateConverter.class)
#JsonProperty(value = "release_date")
private LocalDate releaseDate;
#JsonDeserialize(converter = ApiURLToEntitiesConverter.class)
#ManyToMany(mappedBy = "films")
private List<Person> characters;
#JsonDeserialize(converter = StringToLocalDateTimeConverter.class)
private LocalDateTime created;
#JsonDeserialize(converter = StringToLocalDateTimeConverter.class)
private LocalDateTime edited;
private String url;
}
Entity Person
#Data
#Entity
public class Person extends Persistent<Long> {
private String name;
private String height;
private String mass;
#JsonProperty(value = "hair_color")
private String hairColor;
#JsonProperty(value = "skin_color")
private String skinColor;
#JsonProperty(value = "eye_color")
private String eyeColor;
#JsonProperty(value = "birth_year")
private String birthYear;
private String gender;
#JsonDeserialize(converter = ApiURLToEntityConverter.class)
#JoinColumn(name = "planet_id", foreignKey = #javax.persistence.ForeignKey(name = "none"))
#OneToOne(optional = true)
private Planet homeworld;
#JsonDeserialize(converter = ApiURLToEntitiesConverter.class)
#ManyToMany
#JoinTable(
name = "film_person",
joinColumns = #JoinColumn(name = "film_fk", referencedColumnName = "id", nullable = true),
inverseJoinColumns = #JoinColumn(name = "person_fk", referencedColumnName = "id", nullable = true))
private List<Film> films;
#JsonDeserialize(converter = StringToLocalDateTimeConverter.class)
private LocalDateTime created;
#JsonDeserialize(converter = StringToLocalDateTimeConverter.class)
private LocalDateTime edited;
private String url;
}
I am trying to use the spring jpa method to saveAll
#Override
public List<T> insertAll(List<T> entities) {
for (Persistent entity : entities) {
Set<ConstraintViolation<Persistent>> violations = validator.validate(entity);
if (violations != null && !violations.isEmpty()) {
throw new ConstraintViolationException(violations);
}
}
return repository.saveAll(entities);
}
Converter Method
#Override
public List convert(List<String> s) {
if (s == null || s.isEmpty()) {
return null;
}
List objetos = new LinkedList();
for (String url : s) {
if (url.contains("people")) {
objetos.add(Util.getPerson(url));
}
if (url.contains("planets")) {
objetos.add(Util.getPlanet(url));
}
if (url.contains("starships")) {
objetos.add(Util.getStarship(url));
}
if (url.contains("vehicles")) {
objetos.add(Util.getVehicle(url));
}
if (url.contains("species")) {
objetos.add(Util.getSpecie(url));
}
}
return objetos;
}
}
Util method
public static Person getPerson(String characterApiUrl) {
if (characterApiUrl == null || characterApiUrl.isEmpty()) {
return null;
}
Person person = new Person();
person.setId(StringUtil.getIdEntity(characterApiUrl, "people/"));
return person;
}
The relationship table is being created but no populated