Set creation and update time with Hibernate in Xml mappings

Question

Hi,
I'm using Hibernate with Xml mappings. I have an entity that has two fields creationDate and updateDate of type timestamp, that have to be filled with the current UTC time when the entity is persisted and updated. I know about the existence of the @PrePersist and @PreUpdate annotations, but i don't know how to use their equivalent in my Xml mappings.

Again, i was wondering if Hibernate somehow supports natively the update and creation time set.

Thanks

Answer 1

Timestamps in Hibernate are apparently always updated automatically when the entity changes, so you can't use a <timestamp> mapping for the creation date. However, you can store it as a simple java.util.Date property, initialized it with new Date().

For the update timestamp, try this:

public class MyEntity {
  ...
  private Date updateDate;
  ...
}

<class name="MyEntity" table="MY_ENTITY">
  <id .../>
  <timestamp name="updateDate" access="field" column="UPDATE_DATE"/>
  ...
</class>

Note that timestamp must come right after id in the mapping.

FYI here is a reference of the timestamp attributes.