Apache Tomcat connection to PostgreSQL database (via JDBC driver)

Question

I have installed PostgreSQL 9.5.2 (rhel 6.7 x64) and Apache Tomcat 7.0.73(x64 rhel 6.7) after this i have downloaded postgresql-9.4.1212.jar jar file and paste to Catalina_home/Lib path and adding this following to content.xml file

<Resource auth="Container" name="jdbc/postgres" type="javax.sql.DataSource" user="sarkhan" password="1"
            driverClassName="org.postgresql.Driver" url="jdbc:postgresql://172.29.92.162:5432" maxActive="150"
            schema="test" maxIdle="4"/>

Adding Following to web.xml file

<resource-ref>
    <description>postgreSQL Datasource</description>
    <res-ref-name>jdbc/postgres</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
</resource-ref>

So how can i test that Apache Tomcat Server is connected to PostgreSQL database server?

Answer 1

Tomcat has given a guide of JNDI Datasource HOW-TO, specifically:

4. Accessing the datasource

   When accessing the datasource programmatically, remember to prepend java:/comp/env to your JNDI lookup, as in the following snippet of code. Note also that "jdbc/postgres" can be replaced with any value you prefer, provided you change it in the above resource definition file as well.

InitialContext cxt = new InitialContext();
if ( cxt == null ) {
   throw new Exception("Uh oh -- no context!");
}

DataSource ds = (DataSource) cxt.lookup( "java:/comp/env/jdbc/postgres" );

if ( ds == null ) {
   throw new Exception("Data source not found!");
}