Spring 启动 - 实体：如何添加 CreatedDate（UTC 时区感知）、LastModifiedDate（UTC 时区感知）、CreatedBy、LastModifiedBy

Question

我是 Spring 引导的新手。 我打算使用 postgresql 数据库。 我正在使用 spring 数据 JPA

在这个实体中，我需要添加这些字段

@Entity
@Table(name="STUDENT")
public class Student {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;
    
    @Column(name="STUDENT_NAME", length=50, nullable=false, unique=false)
    private String name;

    Here i want to add
    createdby, modifiedby <--
   
    createdat, modifiedat <-- (i want them to be timezone aware)
    
    // other fields, getters and setters
}

我怎样才能做到这一点。

我来自 django 背景，我们只是在那里

class Student(models.Model):

   ... other fields
   created_at = models.DateTimeField(auto_now_add=True)
   updated_at = models.DateTimeField(auto_now=True)
   created_by = models.ForeignKey(User,related_name="%(app_label)s_%(class)s_created_by",on_delete=models.CASCADE)

Answer 1

您可以使用@PrePersist和@PreUpdate方法。 例如：

@Entity
public class SomeEntity {

    //..other properties..//

    private LocalDateTime createDate;
    private LocalDateTime modifyDate;
    private String createdBy;
    private String modifiedBy;

    @PrePersist
    private void beforeSaving() {
        createDate = LocalDateTime.now();
        createdBy = Thread.currentThread().getName(); //todo: put your logic here
    }

    @PreUpdate
    private void beforeUpdating() {
        modifyDate = LocalDateTime.now();
        modifiedBy = Thread.currentThread().getName(); //todo: put your logic here
    }
}

此外，如果您想在所有实体中使用此类方法，您可以创建BaseEntity并在其他类中扩展它，例如：

@MappedSuperclass
public class BaseEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private LocalDateTime createDate;
    private LocalDateTime modifyDate;
    private String createdBy;
    private String modifiedBy;

    @PrePersist
    private void beforeSaving() {
        createDate = LocalDateTime.now();
        createdBy = Thread.currentThread().getName(); //todo: put your logic here
    }

    @PreUpdate
    private void beforeUpdating() {
        modifyDate = LocalDateTime.now();
        modifiedBy = Thread.currentThread().getName(); //todo: put your logic here
    }

    //..getters/setters omitted..//
}

和

@Entity
public class SomeEntity extends BaseEntity{
    //..other properties..//
}