Spring Data JPA：在save（）方法之后获取实体中的数据

Question

I'm using Spring Data JPA with Hibernate JPA provider in my project. Inside my service I have a method, which saves an entity in database and than using returned object I try to fetch more details about this entity. As a result, details are not fetched. In logs I see only insert statement, without select for details.

Here is my code:

Configuration:

@Configuration
@Profile("test")
@EnableJpaRepositories(basePackages = {"pl.lodz.uml.sonda.common.repositories"})
@EnableTransactionManagement
@PropertySource(value = "classpath:db.test.properties")
public class PersistenceConfigTest {
  @Autowired
  private Environment env;
  @Value("classpath:sql/test-initialization.sql")
  private Resource sqlInitializationScript;

  @Bean
  public DataSource dataSource() {
    BasicDataSource dataSource = new BasicDataSource();

    dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
    dataSource.setUrl(env.getProperty("jdbc.url"));
    dataSource.setUsername(env.getProperty("jdbc.username"));
    dataSource.setPassword(env.getProperty("jdbc.password"));

    return dataSource;
  }

  @Bean
  public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean entityManagerFactory = new LocalContainerEntityManagerFactoryBean();
    HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();

    adapter.setShowSql(env.getProperty("hibernate.showSQL", Boolean.class));
    adapter.setGenerateDdl(env.getProperty("hibernate.hbm2ddl", Boolean.class));

    entityManagerFactory.setDataSource(dataSource());
    entityManagerFactory.setPackagesToScan("pl.lodz.uml.sonda.common.domains");
    entityManagerFactory.setJpaVendorAdapter(adapter);

    Properties properties = new Properties();
    properties.put("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));

    entityManagerFactory.setJpaProperties(properties);

    return entityManagerFactory;
  }

  @Bean(name = "transactionManager")
  public PlatformTransactionManager platformTransactionManager() {
    EntityManagerFactory entityManagerFactory = entityManagerFactory().getObject();
    return new JpaTransactionManager(entityManagerFactory);
  }

  @Bean
  public DataSourceInitializer dataSourceInitializer() {
    ResourceDatabasePopulator populator = new ResourceDatabasePopulator();
    populator.addScript(sqlInitializationScript);

    DataSourceInitializer initializer = new DataSourceInitializer();
    initializer.setDataSource(dataSource());
    initializer.setDatabasePopulator(populator);
    initializer.setEnabled(env.getProperty("db.initialization", Boolean.class));

    return initializer;
  }

  @Bean
  public ProbeService probeService() {
    return new ProbeServiceImpl();
  }
}

Service:

@Service
@Transactional
public class ProbeServiceImpl implements ProbeService {
  @Autowired
  private ProbeRepository probeRepository;

  @Override
  public Probe saveProbe(Probe probe) {
    Probe saved = probeRepository.save(probe);
    saved.getGroup().getName();

    return saved;
  }
}

Simple test:

@RunWith(SpringJUnit4ClassRunner.class)
@ActiveProfiles("test")
@ContextConfiguration(classes = {PersistenceConfigTest.class})
@Transactional
@TransactionConfiguration(defaultRollback = true)
@TestExecutionListeners({
  DependencyInjectionTestExecutionListener.class,
  DirtiesContextTestExecutionListener.class,
  TransactionalTestExecutionListener.class
})
public class ProbeServiceImplTest {
  @Autowired
  private ProbeService probeService;

  @Test
  public void test() {
    Probe probe = ProbeFixtures.generateProbeSample("Test one");
    probe.setGroup(ProbeFixtures.generateProbeGroupSample(1));

    Probe saved = probeService.saveProbe(probe);
    System.out.println("Group name: " + saved.getGroup().getName());
  }
}

Entities:

@Entity
@Table(name = "probes")
public class Probe {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "probe_id")
  private long probeId;

  @Column(name = "probe_title", nullable = false)
  private String title;

  @Column(name = "probe_description", nullable = true)
  private String description;

  @ManyToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "probe_group_id", nullable = true)
  private ProbeGroup group;

  @OneToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "probe_image_id", nullable = true)
  private ProbeFile image;

  @Column(name = "probe_published_date", nullable = false)
  private Date published;

  @Column(name = "probe_last_updated_date", nullable = false)
  private Date updated;

  @Column(name = "probe_expire_date", nullable = false)
  private Date expires;

  @Column(name = "probe_is_active", nullable = false)
  private boolean isActive;

  @OneToMany(mappedBy = "probe", fetch = FetchType.LAZY)
  private List<Question> questions;

  @OneToMany(mappedBy = "probe", fetch = FetchType.LAZY)
  private List<Vote> votes;

  public Probe() {
    questions = new LinkedList<>();
    votes = new LinkedList<>();
  }
  // getters & setters ...


@Entity
@Table(name = "probe_groups")
public class ProbeGroup {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "probe_group_id")
  private long probeGroupId;

  @Column(name = "probe_group_name", nullable = false, unique = true)
  private String name;

  @Column(name = "probe_group_description", nullable = true)
  private String description;

  @OneToMany(mappedBy = "group", fetch = FetchType.LAZY)
  private List<Probe> probes;

  public ProbeGroup() {
    probes = new LinkedList<>();
  }
  // getters & setters ...

And few last logs lines:

Hibernate: insert into probes (probe_description, probe_expire_date, probe_group_id, probe_image_id, probe_is_active, probe_published_date, probe_title, probe_last_updated_date) values (?, ?, ?, ?, ?, ?, ?, ?)
Group name: null

I also tried to run spring data jpa method - getOne(id) after save(), but also it does not work (insert statement invoked, select not);

UPDATE: I removed @Transactional annotaion from my service and from test. Now when I'm saving an entity and then fetching the same entity, I have two sql statements in logs: insert and then select. Maybe my problem is because of wrong persistence/transaction configuration. What You think?

Answer 1

这可能有点过时，但我遇到了同样的问题，发现hibernate二级缓存是个问题。

Answer 2

The save() method may or may not write your changes to database immediately. If you want to commit the changes immediately, you will need to use T saveAndFlush(T entity) method.

Answer 3

The print statement is returning null because, only the getName() returns null. That means your data is getting saved, and the object is returned back. If the "saved" object was null, it should have thrown a null pointer exception.