我正在尝试实现基本的用户/角色

用户可以具有零到多个角色。

public enum Role {
  ROLE_USER,
  ROLE_ADMIN;
}

@Entity
@Table(name = "USERS")
public class User implements Serializable {

  private static final long serialVersionUID = 2936736450886451500L;
  private Long id;
  private Individual individual;
  private Set<Role> roles = new HashSet<Role>();

  @Id
  @Column(name = "ID")
  @GeneratedValue
  public Long getId() {
    return id;
  }

  @SuppressWarnings("unused")
  private void setId(Long id) {
    this.id = id;
  }

  @ElementCollection(targetClass=Role.class)
  @JoinTable(name = "USER_ROLES", joinColumns = @JoinColumn(name = "USER_ID"))
  @Enumerated(EnumType.STRING)
  @Column(name = "role", nullable = false)
  public Set<Role> getRoles() {
    return roles;
  }

  public void setRoles(Set<Role> roles) {
    this.roles = roles;
  }

  public void addRole(Role role) {
    roles.add(role);
  }

}

我的单元测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:/META-INF/spring/resources/resource-context.xml", "classpath:/META-INF/spring/services/persistence-context.xml"})
public class UserDaoJpaImplTest {

@Autowired
UserDao userDao;

@Transactional
@Test
public void testCreate() {
    User user = new User();
    user.setIndividual(new Individual());
    user.addRole(Role.ROLE_USER);
    user.addRole(Role.ROLE_ADMIN);
    userDao.create(user);

    Assert.assertNotSame(user.getId(), 0);
}

问题是，jpa（由hibernate支持）没有在USER_ROLES表上进行插入（正在正确创建它，并且具有正确的复合PK（ROLE，USER_ID）和FK给用户）。

我可以在控制台中看到，用户只完成了一次插入

Hibernate: insert into USERS (INDIVIDUAL_ID) values ( ? )
Hibernate: insert into INDIVIDUALS values ( )

我想我只是缺少一些简单的东西。