[TIL] Spring Basics - Applying JPA Auditing

What to do today

What I studied

Apply JPA Auditing

Timestamped

• Spring Data JPA provides JPA Auditing, a function that automatically enters time values.
  • Data creation (created_at) and modification (modified_at) times are very frequently used for various data.
  • It is inefficient to write the creation and modification time of each entity every time.

    @Getter
    @MappedSuperclass
    @EntityListeners(AuditingEntityListener.class)
    public abstract class Timestamped {
    
    @CreatedDate
    @Column(updatable = false)
    @Temporal(TemporalType.TIMESTAMP)
    private LocalDateTime createdAt;
    
    @LastModifiedDate
    @Column
    @Temporal(TemporalType.TIMESTAMP)
    private LocalDateTime modifiedAt;
    }
    

• @MappedSuperclass: When JPA Entity classes inherit the abstract class, member variables declared in the abstract class, such as createdAt and modifiedAt, can be recognized as columns.
• @EntityListeners(AuditingEntityListner.class): Includes Auditing function in the class.
• @CreateDate: The time is automatically saved when an Entity object is created and saved.
  • The update = false option was added because the initial creation time is stored and cannot be modified after that.
• @LastModifiedDate: When changing the value of the searched Entity object, the changed time is automatically saved.
  • Whenever a change occurs after the initial creation time is saved, it is updated to the corresponding change time.
• @Temporal: Used when mapping date types (java.util.Date, java.util.Calender)
  • There are three separate types in DB: Date, Time, and Timestamp.

Add @EnableJpaAuditing to the class with @SpringBootApplication!

• @EnableJpaAuditing must be added to convey information that the JPA Auditing function will be used.

Problems & Errors

What to do tomorrow