@Temporal Annotation in JPA

1. Temporal annotation

The java.util or java.time properties need to explicitly mark the SQL type correlation with the @Temporal annotation prior to Java 8. @Temporal should only be set on a java.util.Date or java.util.Calendar property.

• @Temporal  annotation must be specified for persistent fields or properties of type java.util.Date and java.util.Calendar.
• In JPA, @Temporal annotation solves the one of the major issue of converting the date and time values from Java object to compatible database type and retrieving back to the application.
• The mapping between the Java 8 Date/Time classes and the SQL types is implicit, there is not need to specify the @Temporal annotation.

• JPA supports  TemporalType.TIMESTAMP, TemporalType.DATE, TemporalType.TIME.
• These types are equivalent of  java.sql.Timestamp, java.sql.Date, java.sql.Time.

Technologies Used in following example :

• JPA 2.1
• Hibernate 5.2.6
• MySql 8.0
• Maven 3
• Spring Tool Suite (STS) 3.9.8
• Java 1.8

2. @Temporal annotation mapping example

@Entity(name="USER")
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    @Column(name = "ID")
    private Long id;
    
    @Column(name="USER_NAME")
    private String userName;
    
    @Column(name="PASSWORD")
    private String password;
    
    @Temporal(value=TemporalType.TIMESTAMP)
    @Column(name="CREATED_TIME")
    private Date creationTime;
    
    @Temporal(value=TemporalType.TIMESTAMP)
    @Column(name="UPDATED_TIME")
    private Date updatedTime;
    
    @Temporal(value=TemporalType.DATE)
    @Column(name="DOB")
    private Date dateofBirth;
    
    @Enumerated(value=EnumType.STRING)
    @Column(name="USER_TYPE")
    private UserType userType;

• From the above snippet line numbers 16,20,24 describes the mapping of Temporal type to the Entity.
• @Temporal annotation more useful to convert specific type either TimeStamp or Time or Date.

3.1 Test the mapping

public static void main( String[] args )
    {
        EntityManagerFactory emf = null;
        EntityManager entityManager = null;
        EntityTransaction transaction = null;
        
        try{
            emf = Persistence.createEntityManagerFactory("jbd-pu");
            entityManager = emf.createEntityManager();
            transaction = entityManager.getTransaction();
            transaction.begin();
            
            User user = new User();
            user.setUserName("mike");
            user.setPassword("password");
            // Setting Current Date
            user.setCreationTime(new Date());
            user.setDateofBirth(new Date());
            user.setUserType(UserType.EMPLOYEE);
    
            entityManager.persist(user);
            transaction.commit();
        }catch(Exception e){
            transaction.rollback();
        }finally{
            entityManager.close();
            emf.close();
        }
    }

Download Application – JPA-Temporal.zip (11 KB)

3.2. You might be interested in following articles

1. Transient annotation in JPA and hibernate
2. Hibernate Types

References

1. Hibernate document