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我正在学习 Spring Framework，我遵循了一些关系 1-1 的教程，所以我定义了我的模型：一个库有一个地址。我从地址中发送我的正文请求库数据和 id，spring 创建记录，但他不能做关系，返回地址null，当我在数据库中进行选择时，address_id没有保存在表库中

这是我尝试过的：

我的模型库：

@Entity
@Table(name = "Bibliotecas")
public class Library implements Serializable {
  private static final long serialVersionUID = 1L;

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

  private String name;

  @OneToOne
  @JoinColumn(name = "address_id", referencedColumnName = "id")
  private Address address;

  public Library() {
  }

  public long getId() {
    return this.id;
  }

  public void setId(long id) {
    this.id = id;
  }

  public String getName() {
    return this.name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Address getAddress() {
    return this.address;
  }

  public void setAddress(Address address) {
    this.address = address;
  }

}

我的模特地址：

@Entity
public class Address {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private long id;

  @Column(nullable = false)
  private String location;

  public long getId() {
    return this.id;
  }

  public void setId(long id) {
    this.id = id;
  }

  public String getLocation() {
    return this.location;
  }

  public void setLocation(String location) {
    this.location = location;
  }

  @OneToOne(mappedBy = "address", fetch = FetchType.LAZY, optional = false)
  private Library library;

}

我的存储库：

public interface LibraryRepository extends JpaRepository<Library, Long> {}
public interface AddressRepository extends JpaRepository<Address, Long> {}

我的图书馆资源：

@RestController
@RequestMapping(value = "/api")
public class LibraryResource {

  @Autowired
  LibraryRepository libraryRepository;

  @GetMapping("/libraries")
  public List<Library> listaBibliotecas() {
    return libraryRepository.findAll();
  }

  @PostMapping("/library")
  public Library salvaBiblioteca(@RequestBody Library library) {
    return libraryRepository.save(library);
  }
}

我在 Postman 中执行此请求：

{
    "name": "library test",
    "address_id": 1
}

Obs：我在数据库中有一个 ID 为 1 的地址，但我收到：

{
    "id": 5,
    "name": "Biblioteca test",
    "address": null
}

为什么我在退货中收到 null ？为什么我的寄存器没有保存address_id？

4

1 回答 1

1

请考虑以下几点：

  • 您切换了地址和库之间的映射
  • 最好在公共字段上使用 Hibernate 注释
  • 地址 -> 库 getter & setter 未实现
  • 地址实体缺少@table 注释

这必须为您工作：

图书馆：

@Entity
@Table(name = "library")
public class Library implements Serializable {

    private static final long serialVersionUID = 1L;

    private long id;
    private String name;
    private Address address;

    public Library() {
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public long getId() {
        return this.id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @OneToOne(mappedBy = "library", cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false)
    public Address getAddress() {
        return this.address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
}

地址：

@Entity
@Table(name = "address")
public class Address {

    private long id;
    private String location;
    private Library library;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public long getId() {
        return this.id;
    }

    public void setId(long id) {
        this.id = id;
    }

    @Column(nullable = false)
    public String getLocation() {
        return this.location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "id")
    public Library getLibrary() {
        return library;
    }

    public void setLibrary(Library library) {
        this.library = library;
    }
}

  • 最好不要将你的存储库暴露给控制器，你应该引用一个可以访问 repositoryDao 的服务。

  • 使用与表名相同的实体名称是更好的方法。

于 2020-05-19T00:08:08.867 回答