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