Tomcat + JNDI DataSource + Spring

One tedious thing to do in project development is to keep track of configurations for different environment.  What happens often in a release is a wrong configuration causing the whole project to be rebuilt.  DataSource is one of the most common configuration.

And when Tech Op suggested to move configuration from project to them, I first started with setting up JNDI DataSource in Tomcat.

On Tomcat side, there are two places need to be configured:
1. Add the JDBC jar to Tomcat's library, for Tomcat 5.5, in common/lib directory.
2. Add the DataSource as a Resource to server.xml under GlobalNamingResources:

<Resource name="myApp" auth="Container"
    type="javax.sql.DataSource"
    driverClassName="oracle.jdbc.OracleDriver"
    url="jdbc:oracle:thin:@<oracle db connection string>"
    username="<user name>" password="<password>"
    maxActive="10" maxIdle="5"
    maxWait="60000" removeAbandoned="true"
    removeAbandonedTimeout="60" logAbandoned="true"/>

Note: removeAbandoned=”true”, removeAbandonedTimeout=”60” and logAbandoned=”true” is Tomcat’s recommended solution to prevent dB connection pool leaks.


On the project side, there are also two places need to be configured:
1. In the web application's root directory, create a META-INF directory if not exists.  And add a context.xml to META-INF with following content:

<Context reloadable="true" >
    <ResourceLink name="jdbc/myApp" global="myApp" type="java.lang.Integer" />
</Context>

context.xml will be copied over to conf/Catalina/localhost with the the project's context name as file name if the file doesn't exist.  So for the first time deployment, it is necessary to check the conf/Catalina/localhost directory and delete the context file if exists.

2. In Spring configuration:

<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
    <property name="jndiName" value="java:comp/env/jdbc/myApp"/>
</bean>

An alternative configuration with jee schema:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
    http://www.springframework.org/schema/jee
    http://www.springframework.org/schema/jee/spring-jee-2.5.xsd">
    ...
    <jee:jndi-lookup id="dataSource" jndi-name="jdbc/myApp"/>
</beans>