java - Spring 数据休息 : Foreign key is update with null after post call in one to many relationship

Question

我正在使用 spring-data-rest。

update 和 daily_update 是一对多关系的 2 个表。使用 spring boot 运行此应用程序。

当我使用 post 请求添加数据时，条目被添加到两个表中而没有任何错误，但在子表 (daily_update) 列“update_id”(更新表的外键)中即将 null。

我正在使用 Lombok 作为 setter 和 getter。

你能帮我解决这个问题吗？

更新实体类:

@Data
@Entity
@Table(name = "update")
public class UpdateEntity {

    @Id
    @Column(name = "id")
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(name = "UUID", strategy = "org.hibernate.id.UUIDGenerator")
    private String id;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @Column(name = "start_time")
    private Date startTime;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @Column(name = "end_time")
    private Date endTime;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @Column(name = "date_created")
    private Date dateCreated;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @Column(name = "date_modified")
    private Date dateModified;

    @OneToMany(mappedBy = "updateEntity", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Set<DailyUpdateEntity> dailyUpdateEntities = new HashSet<>();
}

DailyUpdateEntity 类:

@Data
@Entity
@Table(name = "daily_update")
public class DailyUpdateEntity {

    @Id
    @Column(name = "id")
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(name = "UUID", strategy = "org.hibernate.id.UUIDGenerator")
    private String id;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "update_id")
    private UpdateEntity updateEntity;

    @Column(name = "dimension_id")
    private String dimensionId;

    @Column(name = "hour")
    private Integer hour;

    @Column(name = "updated_type_id")
    private String updatedTypeId;
}

更新存储库:

@RepositoryRestResource(collectionResourceRel = "update", path = "update")
public interface UpdateRepository extends CrudRepository<UpdateEntity, String> {
}

POST 请求来自 postman http://localhost:8080/update

{
    "startTime" : "2016-08-18 10:34:26",
    "endTime" : "2016-08-19 10:34:26",
    "dateCreated" : "2016-06-18 10:34:26",
    "dateModified" : "2016-06-18 10:34:26",
    "dailyUpdateEntities" : 
        [ 
            {
                "dimensionId" : "6ea91f60-2b1d-11e7-93ae-92361f002671",
                "hour" : "01",
                "updatedTypeId" : "6ea9273a-2b1d-11e7-93ae-92361f002671"
            },
            {
                "dimensionId" : "6ea92636-2b1d-11e7-93ae-92361f002671",
                "hour" : "02",
                "updatedTypeId" : "6ea92816-2b1d-11e7-93ae-92361f002671"
            }
        ]
}

并从 spring boot 运行这个应用程序

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Answer 1

我遇到了确切的问题，问题源于表关系的声明。从 UpdateEntity 到 DailyUpdateEntity，您以以下形式声明关系；

@OneToMany(mappedBy = "updateEntity", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
private Set<DailyUpdateEntity> dailyUpdateEntities = new HashSet<>();

通过分离依赖实体的插入和向其添加外键来导致问题。所以第一次创建操作总会缺少外键。通过下面的声明，这个问题就解决了，创建的时候会包含一个外键；

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "update_id", nullable = false, updatable = false)
private Set<DailyUpdateEntity> dailyUpdateEntities = new HashSet<>();