Configure the CData JDBC Driver for PostgreSQL in a Connection Pool in Tomcat

The CData JDBC Drivers support standard JDBC interfaces to integrate with Web applications running on the JVM. This article details how to connect to PostgreSQL data from a connection pool in Tomcat.

Connect to PostgreSQL Data through a Connection Pool in Tomcat

1. Copy the CData JAR and CData .lic file to $CATALINA_HOME/lib. The CData JAR is located in the lib subfolder of the installation directory.
2. Add a definition of the resource to the context. Specify the JDBC URL here.

   To connect to PostgreSQL, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the data provider connects to the user's default database.

   SSH Connectivity for PostgreSQL

   You can use SSH (Secure Shell) to authenticate with PostgreSQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

   SSH Connections to PostgreSQL in Password Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Password"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHPassword: SSH Password

   SSH Connections to PostgreSQL in Public Key Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Public_Key"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHClientCret: the path for the public key certificate file

   Built-in Connection String Designer

   For assistance in constructing the JDBC URL, use the connection string designer built into the PostgreSQL JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

   java -jar cdata.jdbc.postgresql.jar
   

   Fill in the connection properties and copy the connection string to the clipboard.

   👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
   

   You can see the JDBC URL specified in the resource definition below.

   <Resource name="jdbc/postgresql" auth="Container" type="javax.sql.DataSource" driverClassName="cdata.jdbc.postgresql.PostgreSQLDriver" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" url="jdbc:postgresql:User=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432;" maxActive="20" maxIdle="10" maxWait="-1" />
   

   To allow a single application to access PostgreSQL data, add the code above to the context.xml in the application's META-INF directory.

   For a shared resource configuration, add the code above to the context.xml located in $CATALINA_BASE/conf. A shared resource configuration provides connectivity to PostgreSQL for all applications.

3. Add a reference to the resource to the web.xml for the application.

    PostgreSQL data JSP
    jdbc/PostgreSQL
    javax.sql.DataSource
    Container
   
   

4. Initialize connections from the connection pool:

   Context initContext = new InitialContext();
   Context envContext = (Context)initContext.lookup("java:/comp/env");
   DataSource ds = (DataSource)envContext.lookup("jdbc/PostgreSQL");
   Connection conn = ds.getConnection();
    

More Tomcat Integration

The steps above show how to connect to PostgreSQL data in a simple connection pooling scenario. For more use cases and information, see the JNDI Datasource How-To in the Tomcat documentation.