How to connect to DB using JNDI

| October 14, 2011

This is a step-by-step tutorial on connection to database using Java API for a directory service Java Naming and Directory Interface (JNDI) in Jelastic. JNDI allows Java software clients to discover and look up data and objects via a name.

(Jelastic can natively run any Java application with no code changes required so the procedure below is applicable to most Java applications.)

1. Create the environment in Jelastic (with MySQL database in our case)

2. Create a new user in a database:

Read more how to create new user (Database name: jelasticDb; User_name : jelastic; Password : jelastic)
3. Modify configuration files in your web-application:
context.xml:

 <Context antiJARLocking="true" path="/JNDI">
    <Resource name="jdbc/jelasticDb" auth="Container" type="javax.sql.DataSource"
               maxActive="100" maxIdle="30" maxWait="10000"
               username="jelastic" password="jelastic" driverClassName="com.mysql.jdbc.Driver"
               url="jdbc:mysql://mysql.jndi-example.jelastic.com/jelasticDb"/>
</Context>

web.xml:

<resource-ref>
 <description>MySQL Datasource example</description>
 <res-ref-name>jdbc/jelasticDb</res-ref-name>
 <res-type>javax.sql.DataSource</res-type>
 <res-auth>Container</res-auth>
</resource-ref>

4. Finally create a connection in a java-class:

public class MyConnection{
private DataSource dataSource;
public MyConnection() {
try {
InitialContext context = new InitialContext();
dataSource = (DataSource) context.lookup("java:comp/env/jdbc/jelasticDb");
} catch (NamingException ex) {
Logger.getLogger(MyConnection.class.getName()).log(Level.SEVERE, null, ex);
}
}
public Connection getConnection() {
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException ex) {
Logger.getLogger(MyConnection.class.getName()).log(Level.SEVERE, null, ex);
}
return conn;
}