Annotation of Spring Framework [Java]

In this article, I would like to describe annotation of Spring Framework in Java.

🐮 Regarding JPA

@Entity

• @Entity annotation specifies that the class is an entity.
• @Entity is a annotation which indicates a managed object of EntityManager.

@id

• @id applied at the field level to mark the field used for identiy purpose.

@Entity
@IdClass(MyKey.class)
public class YourEntity {
   @Id
   private int id;
   @Id
   private int version;

}

public class MyKey implements Serializable {
   private int id;
   private int version;
}

@Transient

@Transient annotation in JPA is used to indicate that a field is not to be persisted in the database, i.e. their semantics are different.

🎃 @Transactional

Spring’s transaction management @Transactional is generally used when updating/inserting records in multiple tables.

@Service
public class ArticleService {
  @Autowired
  ArticleDao dao;

  // Always start new transaction
  @Transactional(propagation=Propagation.REQUIRES_NEW, isolation = Isolation.READ_COMMITTED)
  public int create(Artice article) {
    return dao.create(article);
  }
}

🚜 Special Thanks

• http://blog.pepese.com/entry/20120613/1339573480
• https://stackoverflow.com/questions/13032948/how-to-create-and-handle-composite-primary-key-in-jpa
• https://stackoverflow.com/questions/2154622/why-does-jpa-have-a-transient-annotation
• https://qiita.com/NagaokaKenichi/items/a279857cc2d22a35d0dd
• https://qiita.com/TakuyaS/items/76a7d16608e7f3b4f9fd

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