This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
You can find a driver by checking the Driver Search Page here. It lists 13 companies that provide Ingres drivers. If you've never used JDBC before, it's probably best to begin by writing a couple of stand-alone applications that access the database before trying to write it in to a servlet. Likewise, if you've never written a servlet, start by configuring the server and writing a couple of simple non-JDBC servlets to start with. JDBC in Servlets is very similar except for a couple of minor differences. Firstly the driver libraries need to be configured in the web-application classpath, not the system classpath. Most people fall over this. Secondly, if you're using a J2EE app server and not just a simple servlet container, you should get Connections via a server-provided DataSource rather than getting them from the DriverManager. This is much the same as using the DriverManager, but the Driver gets configured in the application server and is given a name where it can be found using JNDI. When you connect to the database, you get the DataSource from JNDI by this name and get a Connection from it. This allows the server to manage Connection resources and reduce problems like the time it takes to create a new Connection and applications that try to choke the database, stopping anyone else from getting in. Hope this helps, Dave.