實體更新后@Createdby @CreatedDate 為空

Question

我已經在 Spring 應用程序中實現了審計列，當我創建一個新實體時，列被設置，但當我更新實體時，我發現兩個 @Createdby 和 @CreatedDate 設置為空，我該如何制作這些創建后列不可更改：

@MappedSuperclass
public abstract class Audit implements Serializable {

    @CreatedBy
    private String createdBy;

    @CreatedDate
    private Date createdDate;

    @LastModifiedBy
    private String lastModifiedBy;

    @LastModifiedDate
    private Date lastModifiedDate;
}

Answer 1

對我來說它有效：

@MappedSuperclass
public class Auditor {

    @Column(name = "created_date", updatable = false)
    @CreatedDate
    private long createdDate;

    @Column(name = "modified_date")
    @LastModifiedDate
    private long modifiedDate;

    @Column(name = "created_by", updatable = false)
    @CreatedBy
    private String createdBy;

    @Column(name = "modified_by")
    @LastModifiedBy
    private String modifiedBy;
}

並擴展類：

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Material extends Auditor {

    @Id
    @SequenceGenerator(name = "seq_material", sequenceName = "seq_material")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq_material")
    private Long id;

    @Column
    @NotBlank(message = "Nome é um campo obrigatório!.", groups = validacaoProd.class)
    private String nome;

    More...
}

我更新了數據庫中的記錄：

update material set created_date = 1618418750189, modified_date = 1618418750189 

Answer 2

您可以在類級別使用@DynamicUpdate。 它將只考慮更新列並忽略其他列以放入 UPDATE 查詢。

參考： https : //www.baeldung.com/spring-data-jpa-dynamicupdate