JPA-多对一关系不工作

Question

@Entity
@Table(name = "T_HIKELIST")
public class Hikelist implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private long id;

    @Size(min = 1, max = 50)
    @ManyToOne(optional = false)
    @JoinColumn(name = "login", referencedColumnName = "login")
    private User user;
...
}

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

    @NotNull
    @Size(min = 0, max = 50)
    @Id
    private String login;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "user")
    private Collection<Hikelist> hikeListCollection;
 ...
}

   ...
    @Test
    public void testCreateUser() {
        User user = new User();
        user.setLogin("thomaslogin");
        user.setEmail("[e-mail]");
        user.setPassword("thomas");
        user.setFirstName("thomas");
        user.setLastName("thomas");
        userService.createUser(user);

        Hikelist hike = new Hikelist();
        hike.setId(new Long(1L));
        hike.setLabel("GR20");
        hike.setUser(user);
        hikeService.createHikeList(hike);

        Hikelist hike1 = hikeRepository.findOne(new Long(1L));
        assertNotNull(hike1);
    }

Answer 1

错误是：

javax.validation.UnexpectedTypeException: HV000030: No validator could be found for type: com.breizh.packlight.domain.User

它是由

@Size(min = 1, max = 50)
private User user;

用户的大小如何在1到50之间？