How to use JNDI DataSource provided by Tomcat in Spring?

It is said that in the Spring javadoc article about DriverManagerDataSource class, that this class is very simple and that it is recommended

to use a JNDI DataSource provided by the container. Such a DataSource can be exposed as a DataSource bean in a Spring ApplicationContext via JndiObjectFactoryBean

The question is: how do I accomplish this?

For example, if I wish to have DataSource bean to access my custom MySQL database, what would I require then? What should I write in the context configuration, etc?

Solution 1:

If using Spring's XML schema based configuration, setup in the Spring context like this:

<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.xsd
    http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd">
...
<jee:jndi-lookup id="dbDataSource"
   jndi-name="jdbc/DatabaseName"
   expected-type="javax.sql.DataSource" />

Alternatively, setup using simple bean configuration like this:

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

You can declare the JNDI resource in tomcat's server.xml using something like this:

<GlobalNamingResources>
    <Resource name="jdbc/DatabaseName"
              auth="Container"
              type="javax.sql.DataSource"
              username="dbUser"
              password="dbPassword"
              url="jdbc:postgresql://localhost/dbname"
              driverClassName="org.postgresql.Driver"
              initialSize="20"
              maxWaitMillis="15000"
              maxTotal="75"
              maxIdle="20"
              maxAge="7200000"
              testOnBorrow="true"
              validationQuery="select 1"
              />
</GlobalNamingResources>

And reference the JNDI resource from Tomcat's web context.xml like this:

  <ResourceLink name="jdbc/DatabaseName"
   global="jdbc/DatabaseName"
   type="javax.sql.DataSource"/>

Reference documentation:

• Tomcat 8 JNDI Datasource HOW-TO
• Tomcat 8 Context Resource Links Reference
• Spring 4 JEE JNDI Lookup XML Schema Reference
• Spring 4 JndiObjectFactoryBean Javadoc

Edit: This answer has been updated for Tomcat 8 and Spring 4. There have been a few property name changes for Tomcat's default datasource resource pool setup.

Solution 2:

With Spring's JavaConfig mechanism, you can do it like so:

@Configuration
public class MainConfig {

    ...

    @Bean
    DataSource dataSource() {
        DataSource dataSource = null;
        JndiTemplate jndi = new JndiTemplate();
        try {
            dataSource = jndi.lookup("java:comp/env/jdbc/yourname", DataSource.class);
        } catch (NamingException e) {
            logger.error("NamingException for java:comp/env/jdbc/yourname", e);
        }
        return dataSource;
    }

}

Solution 3:

Assuming you have a "sampleDS" datasource definition inside your tomcat configuration, you can add following lines to your applicationContext.xml to access the datasource using JNDI.

<jee:jndi-lookup expected-type="javax.sql.DataSource" id="springBeanIdForSampleDS" jndi-name="sampleDS"/>

You have to define the namespace and schema location for jee prefix using:

xmlns:jee="http://www.springframework.org/schema/jee"
xsi:schemaLocation="http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd"