Section 5.6. Creating a JNDI Lookup


5.6. Creating a JNDI Lookup

Hibernate is now ready to use. Let's move to the webapp subproject to create the necessary JNDI lookups.

The first step toward using it is creating a JNDI reference to it in jboss-web.xml. Example 5-8 shows what the file looks like now.

Example 5-8. jboss-web.xml
 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE jboss-web PUBLIC "-//JBoss//DTD Web Application 2.3V2//EN"  "http://www.jboss.org/j2ee/dtd/jboss-web_3_2.dtd"> <jboss-web>    <resource-ref>       <res-ref-name>jdbc/JBossAtWorkDS</res-ref-name>       <jndi-name>java:/JBossAtWorkDS</jndi-name>    </resource-ref>    <resource-ref>       <res-ref-name>hibernate/SessionFactory</res-ref-name>       <jndi-name>java:/hibernate/SessionFactory</jndi-name>   </resource-ref> </jboss-web> 

Remember that <res-ref-name> is the local ENC-style name. With the implied java:comp/env/ prefix, the full ENC-style JNDI name for our Hibernate service is java:comp/env/hibernate/SessionFactory.

The global JNDI name (<jndi-name>) matches the setting in hibernate-service.xmljava:/hibernate/SessionFactory.

Example 5-9 shows what the web.xml file now looks like.

Example 5-9. web.xml
 <?xml version="1.0" encoding="UTF-8"?> <web-app  xmlns="http://java.sun.com/xml/ns/j2ee"           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee               http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"           version="2.4">    <servlet>       <servlet-name>Controller</servlet-name>      <servlet-class>com.jbossatwork.ControllerServlet</servlet-class>    </servlet>    <servlet-mapping>       <servlet-name>Controller</servlet-name>       <url-pattern>/controller/*</url-pattern>    </servlet-mapping>    <resource-ref >       <res-ref-name>jdbc/JBossAtWorkDS</res-ref-name>       <res-type>javax.sql.DataSource</res-type>       <res-auth>Container</res-auth>    </resource-ref>    <resource-ref>       <res-ref-name>hibernate/SessionFactory</res-ref-name>       <res-type>net.sf.hibernate.SessionFactory</res-type>       <res-auth>Container</res-auth>    </resource-ref> </web-app> 

Of course, our trusty friend XDoclet does all the file generation, courtesy of the tags in ControllerServlet (Example 5-10).

Example 5-10. ControllerServlet.java
 /**  * @web.servlet  *    name="Controller"  *  * @web.servlet-mapping  *    url-pattern="/controller/*"  *  * @web.resource-ref  *    name="jdbc/JBossAtWorkDS"  *    type="javax.sql.DataSource"  *    auth="Container"  *  * @jboss.resource-ref  *    res-ref-name="jdbc/JBossAtWorkDS"  *    jndi-name="java:/JBossAtWorkDS"  *  * @web.resource-ref  *    name="hibernate/SessionFactory"  *    type="net.sf.hibernate.SessionFactory"  *    auth="Container"  *  * @jboss.resource-ref  *    res-ref-name="hibernate/SessionFactory"  *    jndi-name="java:/hibernate/SessionFactory"  */ public class ControllerServlet extends HttpServle 

Recall that we perform JNDI lookups via the ServiceLocator class in common/src/com/jbossatwork/util. ServiceLocator.getHibernateSessionFactory( ) returns a SessionFactory. Realistically, usually we just need to get a Hibernate Session, so a convenience method in Example 5-11 just returns a Session.

Example 5-11. ServiceLocator.java
 public static SessionFactory getHibernateSessionFactory(                 String jndiSessionFactoryName) throws ServiceLocatorException {         SessionFactory sessionFactory = null;         try {             Context ctx = new InitialContext(  );             sessionFactory = (SessionFactory) ctx.lookup(jndiSessionFactoryName);         } catch (ClassCastException cce) {             throw new ServiceLocatorException(cce);         } catch (NamingException ne) {             throw new ServiceLocatorException(ne);         }         return sessionFactory;     }     public static Session getHibernateSession(                    String jndiSessionFactoryName) throws ServiceLocatorException {         Session session = null;         try         {             session =               getHibernateSessionFactory(jndiSessionFactoryName).openSession(  );         }         catch (Exception e)         {             throw new ServiceLocatorException(e);         }         return session;     } 

For this class to compile, we need to make sure that the Hibernate JARs are on the classpath somewhere. You can either copy the Hibernate jars found in $JBOSS_HOME/server/default/deploy/jboss-hibernate.deployer to common/compile-lib, or refer to them in place as we did in Example 5-12. (Be sure that the environment variable $JBOSS_HOME is defined before you run this.)

Example 5-12. build.xml
 <property name="hibernate.lib.dir"   value="${env.JBOSS_HOME}/server/default/deploy/jboss-hibernate.deployer"/>     <!--    ======================================================  =         This builds the classpath used for compilation.         NOTE: This is independent of your system classpath    ======================================================  =     -->     <path >         <fileset dir="${compile.lib.dir}">             <include name="**/*.jar"/>         </fileset>         <fileset dir="${lib.dir}">             <include name="**/*.jar"/>         </fileset>         <fileset dir="${hibernate.lib.dir}">             <include name="**/*.jar"/>         </fileset>     </path> 



JBoss at Work. A Practical Guide
JBoss at Work: A Practical Guide
ISBN: 0596007345
EAN: 2147483647
Year: 2004
Pages: 197

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