Newbie: using other datasources

[viz]

Hi All,

I have an EntityBean which works fine with the Hypersonic database.

I now want the bean to use mySQL instead of Hypersonic.

I have created the attached mysql-ds.xml and placed it into the /deploy directory.

My question is: What steps should I now take to get the bean to use mySQL instead of Hypersonic?

Any help gratefully received.

Kind regards
--
Viz

[juhalindfors]

configure the datasource in jbosscmp-jdbc.xml of your entity bean; or change the default datasource in standardjbosscmp.xml; or remove the hypersonic datasource configuration and deploy MySQL datasource under java:/DefaultDS

[viz]

Again, many thanks!

Struggling to get things working (being a newbie) I had made too many changes to too many files. So, I deleted my JBoss and reinstalled.

Once I configure the jbosscmp-jdbc.xml and the mysql-ds.xml - it all up and fired!

I must admit I nearly gave up with JBoss, the lack of consise documentation is a big drawback. I plan to put all my findings together into a small document so that other don't go down the same holes I did.

Thanks again.

Kind regards,
--
Marc

[atli]

Generally, you configure a connection pool in your application server configuration files, and access it via the Java Naming and Directory Interface (JNDI). The following code shows how you might use a connection pool:

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import javax.naming.InitialContext;
import javax.sql.DataSource;


public class MyServletJspOrEjb {

public void doSomething() throws Exception {
/*
* Create a JNDI Initial context to be able to
* lookup the DataSource
*
* In production-level code, this should be cached as
* an instance or static variable, as it can
* be quite expensive to create a JNDI context.
*
* Note: This code only works when you are using servlets
* or EJBs in a J2EE application server. If you are
* using connection pooling in standalone Java code, you
* will have to create/configure datasources using whatever
* mechanisms your particular connection pooling library
* provides.
*/

InitialContext ctx = new InitialContext();

/*
* Lookup the DataSource, which will be backed by a pool
* that the application server provides. DataSource instances
* are also a good candidate for caching as an instance
* variable, as JNDI lookups can be expensive as well.
*/

DataSource ds = (DataSource) ctx.lookup("jdbc/MySQLDB");

/*
* The following code is what would actually be in your
* Servlet, JSP or EJB 'service' method...where you need
* to work with a JDBC connection.
*/

Connection conn = null;
Statement stmt = null;

try {
conn = ds.getConnection();

/*
* Now, use normal JDBC programming to work with
* MySQL, making sure to close each resource when you're
* finished with it, which allows the connection pool
* resources to be recovered as quickly as possible
*/

stmt = conn.createStatement();
stmt.execute("SOME SQL QUERY");
stmt.close();

conn.close();
} finally {
/*
* Close any JDBC instances here that weren't
* explicitly closed during normal code path, so
* that we don't 'leak' resources...
*/

if (stmt != null) {
try {
stmt.close();
} catch (SQLException sqlEx) {
// ignore -- as we can't do anything about it here
}

stmt = null;
}

if (conn != null) {
try {
conn.close();
} catch (SQLException sqlEx) {
// ignore -- as we can't do anything about it here
}

conn = null;
}
}
}
}

[jochenwurster]

I am interested in your small documentation. Especially the changes you have made to jbosscmp-jdbc.xml.

Bye Jochen

[jochenwurster]

http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t= be interesting for people having trouble with datasource configuration.

Bye Jochen