java - 为什么 Spring JPA 双向 OneToMany 和 ManyToOne 不更新外键列？

Question

嗨，我正在使用 OneToMany 和 ManyToOne 双向关系学习 Spring JPA，在某些示例中，当我在两侧编写时，我看到 OneToMany 和 ManyToOne 关系，JPA 添加一个新列作为外键列，并从父表。但当我尝试我的时，该列始终是空白的。我的代码如下所示:

这是我的 Account.java 模型:

@Entity
@Table(name = "msAccount")
public class Account {

    @Id
    @NotBlank(message = "Not Blank")
    @Size(min = 0, max = 20)
    public String accountId;

    @NotBlank(message = "Not Blank")
    public String accountName;

    @NotBlank(message = "Not Blank")
    @Email(message = "Should be the right email")
    public String accountEmail;

    @NotBlank(message = "Not Blank")
    @Size(min = 5, message = "Minimal 5 char")
    public String accountAddress;

    @NotBlank(message = "Not Blank")
    public String town;

    @NotBlank(message = "Not Blank")
    public String npwp;

    @NotBlank(message = "Not Blank")
    public String phoneNumber;

    public String fax;

    public String remarks;

    @NotNull
    public Date entryTime;

    @NotNull
    public Boolean active;

    @OneToMany(mappedBy="account", cascade = CascadeType.ALL, orphanRemoval = true)
    public List<Dealer> dealer;

//getter setter skipped

}

这是我的 Dealer.java 模型:

@Entity
@Table(name = "msDealer")
public class Dealer {

    @Id
    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 0, max = 20)
    public String dealerId;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String dealerName;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Email(message = "Masukkan Email yang bener")
    public String dealerEmail;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 5, message = "Minimal 5 karakter")
    public String dealerAddress;

    @ManyToOne(fetch = FetchType.LAZY)
    public Account account;

//getter setter skipped

}

这是我的存储库:

@Repository
public interface AccountRepository extends JpaRepository<Account, Long> {

}

这是我的服务:

@Service
public class AccountService {

    @Autowired
    private AccountRepository accountRepository;

    public Account save(Account account) {
        return accountRepository.save(account);
    }

}

这是我的 Controller :

@RestController
@RequestMapping("/api/account")
public class AccountController {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());
    private final int ROW_PER_PAGE = 10;

    @Autowired
    private AccountService accountService;

    @PostMapping("/new")
    public ResponseEntity<Account> addAccount(@Valid @RequestBody Account account) {
        try {
            Account newAccount = accountService.save(account);
            return ResponseEntity.created(new URI("/api/account/" + newAccount.getAccountId()))
                    .body(account);
        } catch(Exception ex) {
            logger.error(ex.getMessage());
            return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
        }
    }

}

然后我将 JSON 发布到我的保存端点中:

{
  "accountId": "USA001",
  "accountName": "string",
  "accountEmail": "string",
  "accountAddress": "string",
  "town": "string",
  "npwp": "string",
  "phoneNumber": "string",
  "fax": "string",
  "remarks": "string",
  "entryTime": "2020-04-07T15:01:29.404Z",
  "active": true,
  "dealer": [
    {
      "dealerId": "MMO001",
      "dealerName": "string",
      "dealerEmail": "string",
      "dealerAddress": "string"
    }
  ]
}

当我保存它时，终端中显示的 hibernate 看起来正在将查询插入到这两个表中，但是当我检查我的数据库表(postgresql)时，我发现有一个字段“account_account_id”为空，什么我错过这里了吗？

我希望 Hibernate 像这样运行 sql :

insert into account (account_id, account_name, ...etc)
values ('USA001', 1)

insert into dealer (account_account_id, dealer_name, dealer_id, ...etc)
values ('USA001', 'New dealer 1', 'MMO001')

这是我经过一番尝试后更新的模型:

我的帐户.java我删除了cascade = CascadeType.ALL，orphanRemoval = true

@Entity
@Table(name = "msAccount")
public class Account {

    @Id
    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 0, max = 20)
    public String accountId;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String accountName;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Email(message = "Masukkan Email yang bener")
    public String accountEmail;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 5, message = "Minimal 5 karakter")
    public String accountAddress;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String town;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String npwp;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String phoneNumber;

    public String fax;

    public String remarks;

    @NotNull
    public Date entryTime;

    @NotNull
    public Boolean active;

    @OneToMany(mappedBy="account")
    // @JoinColumn(name = "accountId")
    public List<Dealer> dealer;

//getter setter skipped

}

这是我的 Dealer.java。添加了@JoinColumn:

@Entity
@Table(name = "msDealer")
public class Dealer {

    @Id
    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 0, max = 20)
    public String dealerId;

    @NotBlank(message = "Tidak Boleh Kosong")
    public String dealerName;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Email(message = "Masukkan Email yang bener")
    public String dealerEmail;

    @NotBlank(message = "Tidak Boleh Kosong")
    @Size(min = 5, message = "Minimal 5 karakter")
    public String dealerAddress;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "account_id")
    public Account account;

//getter setter skipped

}

现在错误变得很奇怪，我在保存 JSON 数据时收到此错误

> "Unable to find com.api.b2b.Model.Dealer with id MMO001; nested
> exception is javax.persistence.EntityNotFoundException: Unable to find
> com.api.b2b.Model.Dealer with id MMO001"

在一些教程中它有效，但我的却不行，我做错了什么？

这是我的 github 存储库:https://github.com/Fly-Away/LearningSpring

Answer 1

您缺少@JoinColumn在 child 方面:

@Entity
@Table(name = "ms_dealer")
public class Dealer {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "account_account_id")
    public Account account;

    // other fields

}

您已使用mappedBy在父端，但在子端没有映射。您需要指出 Dealer是关系所有者 - 它具有外键。

编辑:如果您要保留(而不是合并)Account实体及其子实体，您不应传递子实体的 id。 (实际上，在持久化时传递任何 id 是一种代码味道，而且很可能是性能 killer 。)使用的 json 应该如下所示:

{
  "accountName": "string",
  "accountEmail": "string",
  "accountAddress": "string",
  "town": "string",
  "npwp": "string",
  "phoneNumber": "string",
  "fax": "string",
  "remarks": "string",
  "entryTime": "2020-04-07T15:01:29.404Z",
  "active": true,
  "dealer": [
    {
      "dealerName": "string",
      "dealerEmail": "string",
      "dealerAddress": "string"
    }
  ]
}

在保存之前可能还需要双方同步:

account.getDealer().forEach(d -> d.setAccount(account));

编辑:

来自 Author编辑必须级联到子级:

@OneToMany(mappedBy = "account", cascade = CascadeType.ALL, orphanRemoval = true)
public List<Dealer> dealer;

您还可以添加@JsonIgnore超过Action或List<Dealer>以避免序列化为 json 时发生堆栈溢出。