Spring Boot 4 Microservices & REST APIs · 课时

使用 @CreatedDate 进行审计

自动跟踪实体的创建和变更

使用 @CreatedDate 进行审计 是 CoddyKit 上的免费 Spring Boot 4 Microservices & REST APIs 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Spring Boot 4 Microservices & REST APIs 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Spring Boot 4 Microservices & REST APIs 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

What is JPA Auditing

Auditing automatically tracks who created or modified an entity and when, without manual code in every save.

Spring Data JPA fills audit fields on insert and update for you.

Enabling Auditing

Add @EnableJpaAuditing to a configuration class to activate the feature.

@Configuration
@EnableJpaAuditing
public class JpaConfig {
}

Registering the Listener

Annotate audited entities with @EntityListeners(AuditingEntityListener.class) so the callbacks fire.

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Product {
    @Id @GeneratedValue
    private Long id;
}

@CreatedDate

@CreatedDate is set once when the entity is first persisted.

@CreatedDate
private Instant createdAt;

@LastModifiedDate

@LastModifiedDate updates on every save, including updates.

@LastModifiedDate
private Instant updatedAt;

A Complete Audited Entity

Putting the timestamp fields together.

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Product {
    @Id @GeneratedValue
    private Long id;

    @CreatedDate
    private Instant createdAt;

    @LastModifiedDate
    private Instant updatedAt;
}

Auditing the User

@CreatedBy and @LastModifiedBy record who made the change.

@CreatedBy
private String createdBy;

@LastModifiedBy
private String modifiedBy;

AuditorAware

To populate the user fields, provide an AuditorAware bean that returns the current principal.

@Bean
public AuditorAware<String> auditorProvider() {
    return () -> Optional.of(
        SecurityContextHolder.getContext()
            .getAuthentication().getName());
}

Reusable Base Class

Put audit fields in a @MappedSuperclass so all entities inherit them.

@MappedSuperclass
@EntityListeners(AuditingEntityListener.class)
public abstract class Auditable {
    @CreatedDate
    private Instant createdAt;
    @LastModifiedDate
    private Instant updatedAt;
}

Choosing a Date Type

Audit fields can be Instant, LocalDateTime, or Long. Configure the reference via dateTimeProviderRef if needed.

Verifying Auditing

On the first save createdAt and updatedAt are equal; after an update, only updatedAt changes.

Product p = repository.save(new Product());
// createdAt == updatedAt
p.setName("New");
repository.save(p);
// updatedAt is now later than createdAt

Quick Check

Test your understanding of auditing.

Recap

You learned automatic auditing:

@EnableJpaAuditing turns it on
@EntityListeners(AuditingEntityListener.class) on entities
@CreatedDate / @LastModifiedDate for timestamps
AuditorAware populates @CreatedBy

常见问题解答

「使用 @CreatedDate 进行审计」课时是免费的吗？

是的 — 「使用 @CreatedDate 进行审计」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Spring Boot 4 Microservices & REST APIs 课程的其余内容，请升级到 CoddyKit PRO。 Spring Boot 4 Microservices & REST APIs 课程共包含 4 节课。

「使用 @CreatedDate 进行审计」这节课中我会学到什么？

自动跟踪实体的创建和变更你通过在浏览器中直接运行的动手代码来练习 Spring Boot 4 Microservices & REST APIs，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Spring Boot 4 Microservices & REST APIs 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Spring Boot 4 Microservices & REST APIs 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「使用 @CreatedDate 进行审计」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Spring Boot 4 Microservices & REST APIs 课中编写并运行代码吗？

能。每节 Spring Boot 4 Microservices & REST APIs 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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