How to use JNDI DataSource provided by Tomcat in Spring?

java

jndi

spring-configuration

tomcat-configuration

byAlex Kataev·Dec 5, 2024

To connect a Spring application to a Tomcat-provided JNDI DataSource, declare a DataSource bean in your applicationContext.xml. Use Spring's jee tag for a simplified lookup:

XML configuration:

<jee:jndi-lookup id="myDataSource" jndi-name="java:comp/env/jdbc/MyDataSource" 
                 expected-type="javax.sql.DataSource"/>

Ensure jndi-name matches the one defined in your Tomcat configuration.

For annotation-based configuration, you could use @Configuration class:

@Bean
public DataSource dataSource() throws NamingException {
    return (DataSource) new InitialContext().lookup("java:comp/env/jdbc/MyDataSource");
}

Lastly, inject myDataSource into your Spring components to leverage Tomcat's managed data source.

DataSource Configuration: Going under the hood

Tailoring DataSource attributes

Optimization is key! Tailor your DataSource properties in server.xml of Tomcat's configuration to neatly fit your application's requirements. Here's how you can do it:

Tomcat server.xml:

<Resource name="jdbc/MyDataSource" auth="Container" type="javax.sql.DataSource"
    maxActive="100" maxIdle="20" validationQuery="SELECT 1" .../>

Reflect these changes in the context.xml of your application so that you stay connected to the right pipeline!

NamingException management

During the JNDI lookup process, you might encounter NamingException being raised. It's time for some exception handling! Utilize a logger to handle these exceptions gracefully.

try {
    dataSource = (DataSource) new InitialContext().lookup(jndiName);
} catch (NamingException e) {
    logger.error("JNDI DataSource lookup failed. The application could not 'lookup' where it left its keys:)", e);
    throw e;
}

Perfecting your JNDI naming game

Make sure to replace jndi-name in your Spring configuration accurately. It should be the same as the one used in Tomcat's context.xml.

Mastering configurations

Harness different configuration strategies for distinct deployment situations:

Centralize your DataSource configuration with a Resource tag in META-INF/Context.xml.
Consult the Tomcat 8 and Spring 4 doc for advanced JNDI and DataSource configuration strategies.

Straightforward configuration

Simplify your Spring's JNDI setup with JndiTemplate in JavaConfig. This helps in swiftly and effectively creating the DataSource bean via JNDI.

@Bean
public JndiTemplate jndiTemplate() {
    return new JndiTemplate();
}

@Bean
public DataSource dataSource(JndiTemplate jndiTemplate) throws NamingException {
    // For folks wondering what JNDI is: Imagine a global phonebook for your app!
    return jndiTemplate.lookup("java:comp/env/jdbc/MyDataSource", DataSource.class);
}