Assuming Jetty 9.1
See: http://www.eclipse.org/jetty/documentation/current/jndi-configuration.html#configuring-datasources
In your WEB-INF/jetty-env.xml
<Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
<New id="db2_pool" class="org.eclipse.jetty.plus.jndi.Resource">
<Arg><Ref refid="wac"/></Arg>
<Arg>jdbc/db2_pool</Arg>
<Arg>
<New class="com.ibm.as400.access.AS400JDBCDataSource">
<Set name="DatabaseName">xxx</Set>
<Set name="ServerName">1.1.1.1</Set>
<Set name="naming">SYSTEM</Set>
<Set name="User">user</Set>
<Set name="Password">pass</Set>
<Set name="URL">jdbc:as400://1.1.1.1;libraries=db2"></Set>
<Set name="libraries">DB2</Set>
</New>
</Arg>
</New>
</Configure>
Then you have a WEB-INF/web.xml section
<resource-ref>
<res-ref-name>jdbc/db2_pool</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
Finally, in your code you access it via ...
import javax.naming.InitialContext;
import javax.sql.DataSource;
public class MyClass {
public void myMethod() {
InitialContext ic = new InitialContext();
DataSource myDS = (DataSource)ic.lookup("java:comp/env/jdbc/db2_pool");
...
}
}