OneToOne-Relation with Spring Boot Rest API and JPA => attempted to assign id from null one-to-one 属性

Question

在我的实际项目中，我使用 Angular 6 进行前端开发，使用 Spring Boot 2 进行后端开发。后端使用 Spring Boot JPA 连接到 Postgres 数据库，我也使用 Spring Boot Rest 创建 API，使用 Spring Boot Rest 创建的默认端点。所以没有手工服务或控制器。

我有一个具有一对一关系的个人实体和地址实体。所有实体都扩展了一个 BaseEntity：

@Data
@MappedSuperclass
@OptimisticLocking(type = OptimisticLockType.DIRTY)
@EntityListeners({AuditingEntityListener.class})
public class BaseEntity {
    @Id
    @GeneratedValue(generator = "uuid2", strategy = GenerationType.AUTO)
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @Type(type = "uuid-binary")
    private UUID id;

    @CreatedDate
    @Temporal(TemporalType.TIMESTAMP)
    private Date createdDate;

    @CreatedBy
    private String createdBy;

    @LastModifiedDate
    @Temporal(TemporalType.TIMESTAMP)
    private Date lastModifiedDate;

    @LastModifiedBy
    private String lastModifiedBy;
}

人

@Data
@Entity
@Table(name = "person")
public class Person extends BaseEntity {
    private String lastName;
    private String firstName;
}

地址

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

    @OneToOne(fetch = FetchType.LAZY, cascade=CascadeType.ALL)
    @MapsId
    private Person person;

    private String street;
    private String houseNumber;
    private String zipCode;
    private String city;
    private String state;
}

我的存储库如下所示：

public interface AddressRepository extends CrudRepository<Address, UUID> {
}

和

public interface PersonRepository extends CrudRepository<Person, UUID> {    
}

当 posting

{
  "street":"exStreet",
  "housenumber":"121",
  "zipcode":"14321",
  "city":"exCity",
  "state":"exState",
  "person":{
    "lastName":"ExampleLastName",
    "firstName":"ExampleFirstName"}
}

到http://localhost:8080/addresses我总是得到以下错误

org.springframework.orm.jpa.JpaSystemException: attempted to assign id from null one-to-one property [Address.person];

连同

org.hibernate.id.IdentifierGenerationException: attempted to assign id from null one-to-one property [Address.person]

看起来服务器没有保留个人实体，尽管没有用于保留地址实体的 ID。我尝试实现这一点：

前端：angular 表单 => 服务 => 使用显示的 json => post 调用 httpclient 到 spring 启动 rest api 服务器// 可行，我认为

后端：spring启动休息api服务器，反序列化json到一个地址和一个人实体=>address.setPerson（人）=>通过jpa保存到数据库

有没有办法通过对 jackson 或其他东西进行一些定制来实现这一点，或者我是否必须再次编写服务和控制器，注意链接，...？我现在已经为此苦苦挣扎了两天，所以非常感谢各种帮助。

编辑经过进一步调查，我确信问题出在映射上。但是我不知道如何注释我的实体或需要进行哪些配置。

Answer 1

好的，我终于成功了。问题确实是映射。我实现了一个自定义反序列化器，并在地址实体上使用 @JsonDeserialize(using = AddressDeserializer.class) 注册了它。见下文。

@Component
public class AddressDeserializer extends StdDeserializer<Address> {

    public AddressDeserializer() {
        super(Address.class);
    }

    @Override
    public Address deserialize(JsonParser jsonParser, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        JsonNode addressNode = jsonParser.getCodec().readTree(jsonParser);

        Person person = new Person();
        person.setLastName(addressNode.get("person").get("lastName").textValue());
        person.setFirstName(addressNode.get("person").get("firstName").textValue());
        System.out.println("##### ----- person.getLastName: " + person.getLastName());

        Address address = new Address();
        address.setPerson(person);
        address.setStreet(addressNode.get("street").textValue());
        address.setHouseNumber(addressNode.get("housenumber").textValue());
        address.setZipCode(addressNode.get("zipcode").textValue());
        address.setCity(addressNode.get("city").textValue());
        address.setState(addressNode.get("state").textValue());

        return address;
    }
}

地址实体：

...
@JsonDeserialize(using = AddressDeserializer.class)
public class Address extends BaseEntity implements Serializable {
...

IntelliJ IDEA 内置 HTTP 客户端： POST http://localhost:8080/addresses 内容类型：application/hal+json 接受：/ 缓存控制：无缓存

{
  "street":"exStreet",
  "housenumber":"121",
  "zipcode":"14321",
  "city":"exCity",
  "state":"exState",
  "person":{
    "lastName":"ExampleLastName",
    "firstName":"ExampleFirstName"}
}

结果地址：

POST http://localhost:8080/addresses

HTTP/1.1 201 
Last-Modified: Sat, 27 Oct 2018 13:50:16 GMT
Location: http://localhost:8080/addresses/89f57064-b4b4-4e1a-adae-142d8c09d834
Content-Type: application/hal+json;charset=UTF-8
Transfer-Encoding: chunked
Date: Sat, 27 Oct 2018 13:50:16 GMT

{
  "id": "89f57064-b4b4-4e1a-adae-142d8c09d834",
  "createdDate": "2018-10-27T13:50:16.803+0000",
  "createdBy": "testsystem",
  "lastModifiedDate": "2018-10-27T13:50:16.803+0000",
  "lastModifiedBy": "testsystem",
  "street": "exStreet",
  "houseNumber": "121",
  "zipCode": "14321",
  "city": "exCity",
  "state": "exState",
  "_links": {
    "self": {
      "href": "http://localhost:8080/addresses/89f57064-b4b4-4e1a-adae-142d8c09d834"
    },
    "address": {
      "href": "http://localhost:8080/addresses/89f57064-b4b4-4e1a-adae-142d8c09d834"
    },
    "person": {
      "href": "http://localhost:8080/addresses/89f57064-b4b4-4e1a-adae-142d8c09d834/person"
    }
  }
}

Response code: 201; Time: 225ms; Content length: 693 bytes

结果人：

{
  "id" : "89f57064-b4b4-4e1a-adae-142d8c09d834",
  "createdDate" : "2018-10-27T13:50:16.808+0000",
  "createdBy" : "testsystem",
  "lastModifiedDate" : "2018-10-27T13:50:16.808+0000",
  "lastModifiedBy" : "testsystem",
  "lastName" : "ExampleLastName",
  "firstName" : "ExampleFirstName",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/persons/89f57064-b4b4-4e1a-adae-142d8c09d834"
    },
    "person" : {
      "href" : "http://localhost:8080/persons/89f57064-b4b4-4e1a-adae-142d8c09d834"
    }
  }
}

数据库：

SELECT * FROM ADDRESS;
CREATED_BY      CREATED_DATE    LAST_MODIFIED_BY    LAST_MODIFIED_DATE      CITY    HOUSE_NUMBER    STATE   STREET      ZIP_CODE    PERSON_ID  
testsystem  2018-10-27 15:50:16.803 testsystem  2018-10-27 15:50:16.803 exCity  121 exState exStreet    14321   89f57064b4b44e1aadae142d8c09d834

SELECT * FROM PERSON;
ID      CREATED_BY      CREATED_DATE    LAST_MODIFIED_BY    LAST_MODIFIED_DATE      FIRST_NAME      LAST_NAME  
89f57064b4b44e1aadae142d8c09d834    testsystem  2018-10-27 15:50:16.808 testsystem  2018-10-27 15:50:16.808 ExampleFirstName    ExampleLastName

就是这样。感谢阅读。

OneToOne-Relation with Spring Boot Rest API and JPA => attempted to assign id from null one-to-one 属性

OneToOne-Relation with Spring Boot Rest API and JPA => attempted to assign id from null one-to-one property

spring-data-rest

spring-boot

jackson-databind