Data Access - Spring Enterprise Recipes: A Problem Solution Approach - page 128

The core programming elements of Hibernate, JPA, and other ORM frameworks resemble those of
JDBC. They are summarized in Table 3-3.

Table 3-3. Core Programming Elements for Different Data Access Strategies

Concept JDBC Hibernate JPA

Connection Session EntityManager Resource

DataSource SessionFactory EntityManagerFactory Resource factory

SQLException HibernateException PersistenceException

Exception

In Hibernate, the core interface for object persistence is Session , whose instances can be obtained
from a SessionFactory instance. In JPA, the corresponding interface is EntityManager , whose instances
can be obtained from an EntityManagerFactory instance. The exceptions thrown by Hibernate are of
type HibernateException , while those thrown by JPA may be of type PersistenceException or other Java
SE exceptions like IllegalArgumentException and IllegalStateException . Note that all these exceptions
are subclasses of RuntimeException , which you are not forced to catch and handle.

Persisting Objects Using the Hibernate API with Hibernate XML Mappings
To map entity classes with Hibernate XML mappings, you can provide a single mapping file for each
class or a large file for several classes. Practically, you should define one for each class by joining the
class name with .hbm.xml as the file extension for ease of maintenance. The middle extension hbm stands
for Hibernate metadata.
The mapping file for the Course class should be named Course.hbm.xml and put in the same package
as the entity class.

<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
" http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<hibernate-mapping package="com.apress.springenterpriserecipes.course">
<class name="Course" table="COURSE">
<id name="id" type="long" column="ID">
<generator class="identity" />
</id>
<property name="title" type="string">
<column name="TITLE" length="100" not-null="true" />
</property>
<property name="beginDate" type="date" column="BEGIN_DATE" />
<property name="endDate" type="date" column="END_DATE" />
<property name="fee" type="int" column="FEE" />
</class>
</hibernate-mapping>