Hibernate – Mapping Date, Time and Timestamp

Learn to map Java temporal classes (date/time) to SQL types while storing the time-based values in the database. We will be learning to map the Java classes from java.time package.

We are not covering the legacy classes such as java.util.Date, java.util.Calendar and classes from java.sql package as they are obsolete now and we should move to updated versions if we have not already.

1. Project Setup

To demonstrate the temporal mappings, we are using Hibernate 6 and in-memory database H2.

<dependency>
    <groupId>org.hibernate.orm</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>6.0.0.Final</version>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>2.1.212</version>
    <scope>test</scope>
</dependency>

Next, we need to setup the SessionFactory for connecting to the database.

2. Mapping Java Types to JDBC Types

In SQL, we have primarily 3 types to store date-time information:

• DATE
• TIME
• TIMESTAMP

There may be a few more types based on the database support.

• TIME_WITH_TIMEZONE
• TIMESTAMP_WITH_TIMEZONE
• TIMESTAMP_UTC
• INTERVAL_SECOND

On the other hand, since Java 8, we have the following java.time classes that can be mapped directly to SQL types:

Hibernate recognizes these types and we only need to provide @Column or @Basic annotation in the field. Hibernate takes care of the choosing correct data types to store/update the values in these fields.

3. Demo

In this demo, we are creating an ArticleEntity. It has 3 fields lastUpdateDate, lastUpdateTime and publishedTimestamp. Their corresponding JDBC types are DATE, TIME and TIMESTAMP.

Notice that we have not used the @Temporal annotation as it is not required with new Java types.

@Entity
@Table(name = "TBL_ARTICLE")
public class ArticleEntity {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "id", nullable = false)
  private Long id;

  @Column
  private String title;

  @Column
  private String content;

  @Column
  private LocalDate lastUpdateDate;

  @Column
  private LocalTime lastUpdateTime;

  @Column
  private LocalDateTime publishedTimestamp;

  //Getters and setters are hidden for brevity
}

Now let us first persist an instance of ArticleEntity and check for the data types in CREATE query.

LocalDate date = LocalDate.of(1990, 1, 1);
LocalTime time = LocalTime.of(10, 10);
LocalDateTime timestamp = LocalDateTime.of(1990, 1, 1, 10, 10);

ArticleEntity article = new ArticleEntity();
article.setTitle("Title");
article.setContent("Content");
article.setLastUpdateDate(date);
article.setLastUpdateTime(time);
article.setPublishedTimestamp(timestamp);

session.persist(article);

The CREATE query generated for this operation is as follows. Notice the JDBC types are date, time and timestamp.

create table TBL_ARTICLE (
    id bigint generated by default as identity,
    content varchar(255),
    title varchar(255),

    lastUpdateDate date,
    lastUpdateTime time,
    publishedTimestamp timestamp(6),

    primary key (id)
)

Now we will fetch this entity from the database and verify that we are able to get the same values that we inserted into the database.

ArticleEntity fetchedArticle = session.get(ArticleEntity.class, article.getId());

Assertions.assertEquals(fetchedArticle.getLastUpdateDate(), date);
Assertions.assertEquals(fetchedArticle.getLastUpdateTime(), time);
Assertions.assertEquals(fetchedArticle.getPublishedTimestamp(), timestamp);

The JUnit test passes successfully indicating that we are able to insert and fetch the Java date-time types into the database.

Happy Learning !!

Sourcecode on Github