Switching to container based datasource…

Quite a time ago had to do this but had no time for posting a complete solution. Read a few articles on that so that I got the idea. Although it looks quite simple you might run into several configuration issues firing weird and long stacktraces. To get rid of those I’ll describe the way it worked for me with some additional comments.

First of all lets assume we use JBoss app server. Different versions of JBoss have their own configuration “specials” so I’ll stick to 5.0.1 jdk 6. First of all we need to register the desired datasource withing the container obtaining a JNDI name. Example configurtion files for registration can be found in [JBoss install dir]/docsexamplesjca. The resulting config file which has to be pout under server/[configuration_name]/deploy would look like

<local-tx-datasource>
    <jndi-name>MySqlDS</jndi-name>
    <connection-url>jdbc:mysql://localhost:3306/mydatasource</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <user-name>user</user-name>
    <password>pwd</password>
    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
    <metadata>
       <type-mapping>mySQL</type-mapping>
    </metadata>
 </local-tx-datasource>

Then in hibernate properties

###### JNDI std JBOSS connection ####################
hibernate.connection.datasource = java:MySqlDS  
hibernate.transaction.factory_class = org.hibernate.transaction.JTATransactionFactory
hibernate.transaction.manager\_lookup\_class = org.hibernate.transaction.JBossTransactionManagerLookup

Deploying your app, especially if you deployed with Tomcat compatibility you might see the next exception on startup:

ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/mydb]] (main) Exception starting filter ServiceFilter
java.lang.<b>ClassCastException</b>: com.arjuna.ats.jbossatx.jta.TransactionManagerDelegate cannot be cast to javax.transaction.TransactionManager
at org.hibernate.transaction.JNDITransactionManagerLookup.getTransactionManager(JNDITransactionManagerLookup.java:23)
at org.hibernate.impl.SessionFactoryImpl.SessionFactoryImpl.java:264)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1055)

In short this means that you have a classloader issue having loaded the wrong manager first. Most likely you have the javax-transaction.jar in your bin. Remove it and everything will work fine :).

If you need to set up the very same thing on Tomcat, then you have to keep in mind the next thing

Tomcat is a hybrid sort of environment (neither fish nor fowl) from the standpoint of Hibernate. Tomcat provides a JNDI and DataSource, unlike a standalone application. The DataSource facility should facilitate portability among application servers. But like a standalone environment, Tomcat provides no Transaction Manager. Hence your code must use the Hibernate Transaction Manager, as it would in a standalone application environment

With this in mind you’ll have to configure the server.xml with

<Resource name="jdbc/testdb" auth="Container" 
type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="user" password="pwd" 
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/mydatasource?autoReconnect=true"/>

And web.xml with

<resource-ref>
<description>My datasource</description>
<res-ref-name>jdbc/testdb</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

Then your hibernate.properties configuration would look like:

hibernate.dialect=org.hibernate.dialect.MySQLInnoDBDialect
hibernate.connection.datasource = java:comp/env/jdbc/testdb
hibernate.transaction.factory_class = org.hibernate.transaction.JTATransactionFactory