Programming Tutorials

JDBC and Tomcat context settings

By: Norman Chap in JDBC Tutorials on 2022-10-07  

JDBC (Java Database Connectivity) is a Java API for connecting and interacting with relational databases. Tomcat is a popular web server and servlet container that can also be used to run Java web applications.

To use JDBC with Tomcat, you need to follow these steps:

1. Add the JDBC driver library to Tomcat's classpath: The JDBC driver library for your specific database needs to be added to Tomcat's classpath. You can do this by copying the JAR file to Tomcat's lib directory.

2. Configure the database connection: You need to configure the database connection in a Tomcat context file. A context file is an XML file that contains configuration settings for a specific web application. You can create a context file with the following contents:

<Context>
  <Resource name="jdbc/MyDB" auth="Container" type="javax.sql.DataSource"
            username="myuser" password="mypassword"
            driverClassName="com.mysql.jdbc.Driver"
            url="jdbc:mysql://localhost/mydatabase"/>
</Context>

This context file defines a JDBC DataSource named "jdbc/MyDB" that connects to a MySQL database named "mydatabase" running on the local machine. The DataSource is configured with a username and password for authentication, and the JDBC driver class name and connection URL.

3. Use the database connection in your web application: Once the database connection is configured, you can use it in your web application by looking up the DataSource using a JNDI (Java Naming and Directory Interface) name. You can do this with the following code:

Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource ds = (DataSource) envCtx.lookup("jdbc/MyDB");
Connection conn = ds.getConnection();

This code retrieves the DataSource named "jdbc/MyDB" from the JNDI context and uses it to get a Connection object for the database.

By using JDBC with Tomcat, you can create Java web applications that can store and retrieve data from a relational database.