In the last tutorial we saw how to use @CreatedDate and @LastModifiedDate to implement basic auditing. This tutorial shows how to use @CreatedBy and @LastModifiedBy annotations to track who created and changed an entity.

To use @CreatedBy and @LastModifiedBy annotations, we also need to implement AuditorAware<T> interface and registered it as a bean. The implementation should provide who the current user is. The generic type T specifies the type of annotated fields representing the user.

Quick Example

In following example we are using system logged in user:

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Article {
    ......
   @CreatedBy
   private String createdBy;
   @LastModifiedBy
   private String modifiedBy;
     ......
}

@Component
public class SystemLoggedInUserAuditorAware implements AuditorAware<String> {

  @Override
  public Optional<String> getCurrentAuditor() {
      return Optional.of(System.getProperty("user.name"));
  }
}

Complete Example

Entity

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Article {
    @Id
    @GeneratedValue
    private Long id;
    private String content;
    @CreatedDate
    private LocalDateTime dateCreated;
    @LastModifiedDate
    private LocalDateTime dateModified;
    @CreatedBy
    private String createdBy;
    @LastModifiedBy
    private String modifiedBy;
    .............
}

AuditorAware Implementation

@Component
public class SystemLoggedInUserAuditorAware implements AuditorAware<String> {

    @Override
    public Optional<String> getCurrentAuditor() {
        return Optional.of(System.getProperty("user.name"));
    }
}

Repository

public interface ArticleRepository extends CrudRepository<Article, Long> {
}

Java Config

@EnableJpaRepositories
@EnableJpaAuditing
@ComponentScan
@Configuration
public class AppConfig {

    @Bean
    EntityManagerFactory entityManagerFactory() {
        EntityManagerFactory emf =
                Persistence.createEntityManagerFactory("example-unit");
        return emf;
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory());
        return txManager;
    }
}

Example Client

@Component
public class ExampleClient {
    @Autowired
    private ArticleRepository repo;

    public void run() {
        //creating and persisting an Article
        Article article = new Article("test article");
        repo.save(article);

        //load article
        Optional<Article> optArticle = repo.findById(article.getId());
        Article loadedArticle = optArticle.get();
        System.out.println(optArticle.get());

        //have some delay to see a clear diff in modified time
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        //modify article
        loadedArticle.setContent("modified content");
        repo.save(loadedArticle);

        //load again
        System.out.println(repo.findById(loadedArticle.getId()).get());
    }


    public static void main(String[] args) {
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext(AppConfig.class);
        ExampleClient exampleClient = context.getBean(ExampleClient.class);
        exampleClient.run();
        EntityManagerFactory emf = context.getBean(EntityManagerFactory.class);
        emf.close();
    }
}

Article{id=1, content='test article', dateCreated=2018-12-13T22:47:15.216, dateModified=2018-12-13T22:47:15.216, createdBy='Joe', modifiedBy='Joe'}
Article{id=1, content='modified content', dateCreated=2018-12-13T22:47:15.216, dateModified=2018-12-13T22:47:17.267, createdBy='Joe', modifiedBy='Joe'}

Example Project

Dependencies and Technologies Used:

• spring-data-jpa 2.1.3.RELEASE: Spring Data module for JPA repositories.
  Uses org.springframework:spring-context version 5.1.3.RELEASE
• spring-aspects 5.1.3.RELEASE: Spring Aspects.
• hibernate-core 5.3.7.Final: Hibernate's core ORM functionality.
  Implements javax.persistence:javax.persistence-api version 2.2
• h2 1.4.197: H2 Database Engine.
• JDK 1.8
• Maven 3.5.4