保存实体尝试插入新记录，而不是与以前的记录合并

Question

当通过saveAndFlush持久化/合并父实体时，它将尝试为子实体插入新记录，而不是查找/合并现有记录。 这将导致SQLIntegrityConstraintViolationException错误。 我也尝试过直接通过DAO提取现有实体，将其设置为父实体中的字段，然后保存并刷新，它仍然尝试为子实体字段插入新记录。

任何帮助是极大的赞赏！

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子实体

@Entity
@Table(name = "DROPDOWN_TYPE", uniqueConstraints = {
        @UniqueConstraint(columnNames = { "DROPDOWN_TYPE_TXT" }, name = "DROPDOWN_TYPE_TXT_UK") })
public class DropdownType {

    @Id
    @Column(name = "DROPDOWN_TYPE_TXT")
    private String text;

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        DropdownType that = (DropdownType) o;

        return text.equals(that.text);
    }

    @Override
    public int hashCode() {
        return text.hashCode();
    }
}

上级实体

@Entity
@Table(name = "DROPDOWN", uniqueConstraints = {
        @UniqueConstraint(columnNames = { "DROPDOWN_TXT", "DROPDOWN_TYPE_TXT" }, name = "DROPDOWN_UK") })
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Dropdown {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "DROPDOWN_OPTION_ID_GENERATOR")
    @SequenceGenerator(allocationSize = 1, name = "DROPDOWN_OPTION_ID_GENERATOR", sequenceName = "DROPDOWN_OPTION_ID_SQ")
    @Column(name = "DROPDOWN_OPTION_ID")
    private Long id;

    @ManyToOne(cascade = { CascadeType.MERGE, CascadeType.PERSIST })
    @JoinColumn(name = "DROPDOWN_TYPE_TXT", foreignKey = @ForeignKey(name = "DROPDOWN_TYPE_TXT_FK"))
    private DropdownType dropdownType;

    @Column(name = "DROPDOWN_TXT")
    private String text;

    @Column(name = "ACTIVE_FLG")
    private Boolean active;

    @Column(name = "LEGACY_FLG")
    private Boolean legacy;

    public Long getId() {
        return id;
    }

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

    public DropdownType getDropdownType() {
        return dropdownType;
    }

    public void setDropdownType(DropdownType dropdownType) {
        this.dropdownType = dropdownType;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public Boolean isActive() {
        return active;
    }

    public void setActive(Boolean active) {
        this.active = active;
    }

    public Boolean isLegacy() {
        return legacy;
    }

    public void setLegacy(Boolean legacy) {
        this.legacy = legacy;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Dropdown dropdown = (Dropdown) o;

        return dropdownType.equals(dropdown.dropdownType) && text.equals(dropdown.text);
    }

    @Override
    public int hashCode() {
        int result = dropdownType != null ? dropdownType.hashCode() : 0;
        result = 31 * result + (text != null ? text.hashCode() : 0);
        return result;
    }
}

Answer 1

如果您将hibernate用作JPA提供程序，则在覆盖equals和hashcode时要小心- 请参阅本文

可能是，您的JPA提供程序认为您的实体不相等，因为实际上加载的实体可以是某些CGLIB代理（使用instanceof可能比比较类要好）。