Hibernate.orgCommunity Documentation
This tutorial is located within the download bundle under basic.
Objectives
Use annotations to provide mapping information
Use the native Hibernate APIs
The contents are identical to Section 2.1, “The Hibernate configuration file”, with one important
difference. The mapping element at the very end naming the annotated entity class using
the class attribute.
The entity class in this tutorial is org.hibernate.tutorial.annotations.Event which
follows JavaBean conventions. In fact the class itself is identical to the one in Section 2.2, “The entity Java class”, except that annotations are used to provide the metadata,
rather than a separate hbm.xml file.
Example 3.1. Identifying the class as an entity
@Entity
@Table( name = "EVENTS" )
public class Event {
...
}
The @javax.persistence.Entity annotation is used to mark a class as an entity.
It functions the same as the class mapping element discussed in Section 2.3, “The mapping file”. Additionally the
@javax.persistence.Table annotation explicitly specifies the table
name. Without this specification, the default table name would be EVENT).
Example 3.2. Identifying the identifier property
@Id
@GeneratedValue(generator="increment")
@GenericGenerator(name="increment", strategy = "increment")
public Long getId() {
return id;
}
@javax.persistence.Id marks the property which defines the
entity's identifier. @javax.persistence.GeneratedValue and
@org.hibernate.annotations.GenericGenerator work in tandem
to indicate that Hibernate should use Hibernate's increment generation
strategy for this entity's identifier values.
Example 3.3. Identifying basic properties
public String getTitle() {
return title;
}
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "EVENT_DATE")
public Date getDate() {
return date;
}
As in Section 2.3, “The mapping file”, the date property needs
special handling to account for its special naming and its SQL type.
org.hibernate.tutorial.annotations.AnnotationsIllustrationTest is essentially the
same as org.hibernate.tutorial.hbm.NativeApiIllustrationTest discussed in
Section 2.4, “Example code”.
Practice Exercises
Add an association to the Event entity to model a message thread. Use the
Developer Guide as a guide.
Add a callback to receive notifications when an Event is created, updated or
deleted. Try the same with an event listener. Use the Developer
Guide as a guide.
Copyright © 2004 Red Hat, Inc.