Java Spring：具有附加 ID 的子类中的 ManytoOne EmbeddedId - 在特定于子的 PK 上出现空错误

Question

我能够通过适用于 GET 请求的复合 pk 获得这种多对一关系，但在保存新条目时遇到问题。

我有一个带有嵌入 ID 的父实体。

@Embeddable
public class AnnualServiceHistoryPK implements Serializable {

    @Column(name = "year", columnDefinition = "int(4)")
    Integer year;
    @Column(name = "month", columnDefinition = "char(3)")
    String month;
    @Column(name = "route", columnDefinition = "varchar(32)")
    String route;

这是放在父实体中的：

@Entity(name = "AnnualServiceHistory")
@Table(name = "annual_service_history")
public class AnnualServiceHistory extends Auditable<String> implements Serializable 
{ 
@EmbeddedId
AnnualServiceHistoryPK annualServiceHistoryPK;

... other variables

    @OneToMany(mappedBy = "annualServiceHistory", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    List<AnnualServiceHistoryNonMachine> annualServiceHistoryNonMachineList;

我有一个子实体，它从父实体映射嵌入的 id 并添加和额外的本地 PK。

public class AnnualServiceHistoryNonMachine extends Auditable<String> implements Serializable {

    @Id
    @MapsId
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "year", referencedColumnName = "year")
    @JoinColumn(name = "month", referencedColumnName = "month")
    @JoinColumn(name = "route", referencedColumnName = "route")
    private AnnualServiceHistory annualServiceHistory;

    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "toy_inventory", referencedColumnName = "id")
    ToyInventory toyInventory;

... other variables

我的问题是，当我在级联过程中出于某种原因将父级与子级列表一起保存时，当它生成子密钥时，它只是从 MapsId 部分创建密钥并抱怨 toyInventory 密钥为空.我不确定为什么它会丢失这个 ID，因为在执行存储库保存之前，子类在对象中有 toyInventory 键。

这是我收到的错误： "java.sql.SQLIntegrityConstraintViolationException: 列 'toy_inventory' 不能为空"

Answer 1

找到解决方案。 - https://medium.com/@bhagyajayashani/composite-key-handling-using-idclass-annotation-in-spring-boot-java-26f40bbd38a2

从使用@embeddedId 更改为使用@classId。然后创建一个单独的连接对象，并基于单个变量而不是 EmbeddedId 创建连接。

@Embeddable
public class AnnualServiceHistoryPK implements Serializable {

    Integer year;
    String month;
    String route;

    public AnnualServiceHistoryPK() {
    }

@Entity(name = "AnnualServiceHistory")
@Table(name = "annual_service_history")
@IdClass(AnnualServiceHistoryPK.class)
public class AnnualServiceHistory extends Auditable<String> implements Serializable {

    @Id
    @Column(name = "year", columnDefinition = "int(4)")
    Integer year;

    @Id
    @Column(name = "month", columnDefinition = "char(3)")
    String month;

    @Id
    @Column(name = "route", columnDefinition = "varchar(32)")
    String route;

... other variables ...

    @OneToMany(mappedBy = "annualServiceHistory", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    Set<AnnualServiceHistoryNonMachine> annualServiceHistoryNonMachineList;

@Embeddable
public class AnnualServiceHistoryNonMachinePK implements Serializable {

    Integer year;
    String month;
    String route;
    ToyInventory toyInventory;

    public AnnualServiceHistoryNonMachinePK() {
    }

@Entity(name = "AnnualServiceHistoryNonMachine")
@Table(name = "annual_service_history_non_machine")
@IdClass(AnnualServiceHistoryNonMachinePK.class)
public class AnnualServiceHistoryNonMachine extends Auditable<String> implements Serializable {

    @Id
    @Column(name = "year", columnDefinition = "int(4)")
    Integer year;

    @Id
    @Column(name = "month", columnDefinition = "char(3)")
    String month;

    @Id
    @Column(name = "route", columnDefinition = "varchar(32)")
    String route;

... other variables ...

    @ManyToOne
    @JoinColumns({
            @JoinColumn(name = "year", referencedColumnName = "year", insertable = false, updatable = false),
            @JoinColumn(name = "month", referencedColumnName = "month", insertable = false, updatable = false),
            @JoinColumn(name = "route", referencedColumnName = "route", insertable = false, updatable = false)
    })
    @JsonIgnore
    private AnnualServiceHistory annualServiceHistory;