JPA @OneToMany @ManyToOne双向，集合始终为空

Question

我的@OneToMany @ManyToOne双向关系存在问题，每当我查询该集合时，我都会得到一个空的。我已经阅读了有关在stackoverflow上发布的类似问题，但遗憾的是到目前为止还没有帮助我。

用户模型（OneToMany）

@Entity
public class User {

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

  @JsonBackReference
  @OneToMany(mappedBy = "owner", cascade = CascadeType.ALL)
  private Set<EncryptedSnp> encryptedSnps = new HashSet<>();

  protected User() {}

  public Set<EncryptedSnp> getEncryptedSnps() {
    return encryptedSnps;
  }

  public void setEncryptedSnps(Set<EncryptedSnp> encryptedSnps) {
    this.encryptedSnps = encryptedSnps;
  }

  @Transient
  public void addEncryptedSnp(EncryptedSnp encryptedSnp) {
    this.encryptedSnps.add(encryptedSnp);
    if (encryptedSnp.getOwner() != this) {
      encryptedSnp.setOwner(this);
    }
  }

  // ..
  // some other non-relevant or straightforward property fields, getters, and setters.
}

EncryptedSnp Model（ManyToOne）

@Entity
public class EncryptedSnp {

  private long id;
  private User owner;
  private byte[] value;

  protected EncryptedSnp() {}

  public EncryptedSnp(BigInteger value, User owner) {
    this.value = value.toByteArray();
    this.owner = owner;
  }

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "encrypted_snp_id")
  public long getId() {
    return id;
  }

  @JsonManagedReference
  @ManyToOne
  @JoinColumn(name = "owner_id", nullable = false)
  public User getOwner() {
    return owner;
  }

  @Column(name = "snp_encrypted", nullable = false, columnDefinition = "blob")
  public byte[] getRawValue() {
    return rawValue;
  }

  public void setOwner(User owner) {
    this.owner = owner;
  }

  // ..
  // some other non-relevant or straightforward property fields, getters, and setters.
}

关系的人口

@Autowired
private UserRepo userRepo;

@Transactional
public void addSnps() {
  User snpTestUser = userRepo.findByUsername("snp_test");
  Assert.notNull(snpTestUser);

  EncryptedSnp encryptedSnpA = new EncryptedSnp(getRandomBigInteger(), snpTestUser);
  EncryptedSnp encryptedSnpB = new EncryptedSnp(getRandomBigInteger(), snpTestUser);
  EncryptedSnp encryptedSnpC = new EncryptedSnp(getRandomBigInteger(), snpTestUser);

  snpTestUser.addEncryptedSnp(encryptedSnpA);
  snpTestUser.addEncryptedSnp(encryptedSnpB);
  snpTestUser.addEncryptedSnp(encryptedSnpC);

  userRepo.save(snpTestUser);
}

测试

@Transactional
@RequestMapping(value = "user/snp_test/snps", method = RequestMethod.GET)
public ResponseEntity<Set<EncryptedSnp> getEncryptedSnps() {
  User snpTestUser = userRepo.findByUsername("snp_test");
  Assert.notNull(snpTestUser);

  // size is always 0
  Assert.isTrue(user.getEncryptedSnps().size() > 0);

  // irrelevant
}

PS：'mysql＆gt; select encrypted_id from encrypted_snp'返回3行，其中包含正确的owner_id：

+----------+
| owner_id |
+----------+
|        3 |
|        3 |
|        3 |
+----------+

我希望我已经提供了足够的信息来澄清我的问题。 基本上，我的问题是{user} .getEncryptedSnps（）总是返回一个空集合。