为什么Spring JPA双向OneToMany和ManyToOne没有更新外键列？

Question

嗨，我正在学习Spring JPA使用OneToMany和ManyToOne双向关系，在一些示例中，我看到OneToMany和ManyToOne关系，当我在两个方面编写时，JPA添加一个新列作为外键列，并插入父表中的键值。但当我尝试我的时候，这一栏总是空白的。下面是我的代码的样子：

下面是我的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

}

下面是我的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

}

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

}

@Service
public class AccountService {

    @Autowired
    private AccountRepository accountRepository;

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

}

这里是我的控制器：

@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();
        }
    }

}

然后将JSON发布到保存endpoint：

{
  "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，我的终端中显示的hibernate将查询插入到2表中，但是当我检查我的数据库表（它是postgresql）时，我发现有一个字段“account_account_id”是空的，我错过了什么？

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')

下面是我经过一番尝试后更新的模型：

我的Account.java我删除cascade=CascadeType.all,OlphanRemovation=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

}

@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

}

> "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"

这里是我的github回购：https://github.com/fly-away/learningspring

Answer 1

子端缺少@joincolumn:

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

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

    // other fields

}

您已经在父端使用了mappedby，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：如果您将account实体及其子实体持久化（而不是合并），则不应传递子实体的ID。（实际上，在persist上传递任何ID是一种代码味道，而且很可能是性能杀手。）所使用的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"
    }
  ]
}

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

编辑：

从作者编辑必须级联到子级：

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

您还可以在action或list 上添加@jsonignore以避免序列化到JSON时的堆栈溢出。