在实体管理器上调用合并后，实体丢失 state

Question

我遇到了一个非常烦人的问题，即在 object 合并到 EntityManager 之后，实体会丢失其 state。

在应用程序中有一个带有 ExpenditureStatements 的“档案”，其中包含许多支出。

这些支出可以（部分）向多个债务人索赔。 为 ExpenditureStatement 创建一个 ExpenditureStatementClaim。 为 ExpenditureStatement 上的每个 Expenditure 创建一个 ExpenditureClaim。

ExpenditureClaim 和 ExpenditureStatementClaim 都保持不变，没有任何问题。 然而，在 entitymanager 上的合并被称为：em.merge(dossier) 后，支出将失去其 state。

但是，每个支出中的数据会恢复到数据库中的最后一个 state。

我已经尝试过仅自上而下级联，我已经对 equals/hashcode 进行了更改，但这并没有改变任何东西。

有没有人知道可能导致此问题的原因？

卷宗：

@Entity
@Table(name = "DOSSIER")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "DOSSIER_TYPE", discriminatorType = DiscriminatorType.STRING, length = 48)
public abstract class Dossier  {

@OneToMany(mappedBy = ExpenditureStatement.PROP_DOSSIER, cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
private List<ExpenditureStatement> expenditureStatements = new ArrayList<ExpenditureStatement>();
}

支出报表：

@Entity
@Table(name = "EXPENDITURE_STATEMENT")
public class ExpenditureStatement {
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.MERGE})
@JoinColumn(name = "DOSSIER_ID", nullable = false)
private Dossier dossier;

@OneToMany(mappedBy = Expenditure.PROP_EXPENDITURE_STATEMENT, cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
private List<Expenditure> expenditures = new ArrayList<Expenditure>();

@OneToMany(mappedBy = ExpenditureStatementClaim.PROP_EXPENDITURE_STATEMENT, cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
private Collection<ExpenditureStatementClaim> expenditureStatementClaims = new ArrayList<ExpenditureStatementClaim>();
}

支出：

@Entity
@Table(name = "EXPENDITURE")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "EXPENDITURE_ORIGIN_CD", discriminatorType = DiscriminatorType.STRING, length = 48)
public abstract class Expenditure extends EntityObject<Long> {

@ManyToOne(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "EXPENDITURE_STATEMENT_ID", nullable = false)
private ExpenditureStatement expenditureStatement;

@OneToMany(mappedBy = ExpenditureClaim.PROP_EXPENDITURE, cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
private Collection<ExpenditureClaim> claims = new HashSet<>();

@NotNull
@Column(name = "EXPENDITURE_STATUS_CD", nullable = false)
@Enumerated(EnumType.STRING)
private ExpenditureStatus status;

public abstract BigDecimal getAmount();
}

ExpenditureStatementClaim：

@Entity
@Table(name = "DEEL_STAAT")
public class ExpenditureStatementClaim {    

@NotNull
@ManyToOne(cascade = {CascadeType.MERGE, CascadeType.PERSIST})
@JoinColumn(name = "EXPENDITURE_STATEMENT_ID", nullable = false)
private ExpenditureStatement expenditureStatement;

@OneToMany(mappedBy = ExpenditureClaim.PROP_EXPENDITURE_STATEMENT_CLAIM, cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
private Collection<ExpenditureClaim> expenditureClaims = new ArrayList<>();

@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name = "INVOICE_ID")
private Invoice invoice;
}

支出索赔：

@Entity
@Table(name = "EXPENDITURE_CLAIM")
public class ExpenditureClaim extends EntityObject<Long> {

@ManyToOne(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "EXPENDITURE_ID", nullable = false)
private Expenditure expenditure;

@Column(name = "AMOUNT", precision = NumberConstants.CURRENCY_PRECISION, scale = NumberConstants.CURRENCY_OPERATION_SCALE)
private BigDecimal amount;

@ManyToOne(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "EXPENDITURE_ST_CLAIM_ID", nullable = false)
private ExpenditureStatementClaim expenditureStatementClaim;
}

Answer 1

该问题不是由映射问题引起的，而是由于项目使用的（相当旧的）版本的 EclipseLink 中的一个错误，即新创建的 object 不会级联对现有 object 所做的更改。

https://bugs.eclipse.org/bugs/show_bug.cgi?id=340802

只是一个很好的提醒，只要有可能，您应该尝试更新项目中依赖项的版本......