Play 2.4 JPA/Hibernate EntityManager不刷新数据库

我开始了一个简单的基于JPA的Play 2.4项目,但我在理解分层架构中正确使用Play的EntityManager时遇到了一些问题,特别是在将实体写入数据库的情况下。我是一个初学者,通常我使用Spring进行应用程序开发,几乎没有直接与实体管理器一起工作。

假设我有一个注册新用户的控制器。为了分离关注点,控制器只接受请求,将请求委托给基础服务并返回结果,即我的示例中新创建的注册实体:

public class ApiController extends Controller {

    private final RegistrationService registrationService;

    @Inject
    public ApiController(final RegistrationService registrationService) {
        this.registrationService = registrationService;
    }

    @BodyParser.Of(BodyParser.Json.class)
    @Transactional
    public Result startRegistration() {
        final JsonNode requestBody = request().body().asJson();
        final RegistrationRequest registrationRequest = Json.fromJson(requestBody, RegistrationRequest.class);
        final Registration result = registrationService.startRegistration(registrationRequest);
        return ok(Json.toJson(result));
    }
}

我的Guice模块,它绑定我的依赖项并提供实体管理器,以便我可以将其注入我的服务:

public class RegistrationModule extends AbstractModule {

    protected void configure() {
        bind(TokenGenerator.class).to(TokenGeneratorSupport.class);
        bind(RegistrationService.class).to(RegistrationServiceSupport.class);
    }

    @Provides
    public EntityManager provideEntityManager() {
        EntityManager em = JPA.em("default");
        LOG.info("Created EntityManager: {}", em);
        return em;
    }

    @Provides
    public Validator provideValidator() {
        final ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
        final Validator validator = validatorFactory.getValidator();
        return validator;
}

我的服务层,执行db操作:

public abstract class DefaultJpaServiceSupport<T extends AbstractJpaEntity> implements BaseService<T> {

    private final EntityManager entityManager;
    private final Validator validator;
    private final Class<T> type;

    protected DefaultJpaServiceSupport(final EntityManager entityManager, final Validator validator,
                                   final Class<T> type) {
        this.entityManager = entityManager;
        this.validator = validator;
        this.type = type;
    }

    @Override
    public Optional<T> getByUuid(final UUID uuid) {
        ...
        final TypedQuery<T> query = getEntityManager().createQuery(queryString, getType());
        ...
        return entity;
    }

    protected final EntityManager getEntityManager() {
        return entityManager;
    }
}

public class RegistrationServiceSupport extends DefaultJpaServiceSupport<Registration>
    implements RegistrationService {

    private static final Logger.ALogger LOG = Logger.of(RegistrationServiceSupport.class);

    private final TokenGenerator tokenGenerator;

    @Inject
    protected RegistrationServiceSupport(final EntityManager entityManager, final Validator validator,
                                     final TokenGenerator tokenGenerator) {
        super(entityManager, validator, Registration.class);
        this.tokenGenerator = tokenGenerator;
    }

    @Override
    public Registration startRegistration(final RegistrationRequest request) {
    ...
        final Registration registration = getEntityManager().merge(new Registration.Builder(randomUUID(), request.getEmail(),
            request.getPassword(), tokenGenerator.generate()).build());

        return registration;
    }
} 
}

问题是,getEntityManager().mmerge(..)不写入我的数据库,但调用了我的@PrePersist注释方法,但没有刷新。读取器方法与getEntityManager()配合使用很好。我已经尝试用JPA.withTransaction(…)包装merge(..),但没有任何区别。

但是,当我将其更改为JPA.em().mmerge(..)时,它会正常工作,实体被写入数据库。 但是,在我的服务中,我有一个丑陋的依赖关系,这是我真正想要避免的,这就是为什么我在模块中为依赖注入提供实体管理器。

也许在我的设计中有一个我看不到的问题,但这是由我在春天的经历推动的。

每一个想法都很受欢迎,我真的很执着于此,在其他地方找不到任何想法,Play文档在这种情况下也没有帮助。

谢谢!