How to use BTM as the transaction manager in Tomcat 6.x

These instructions have been verified against BTM 1.3.1.


Step 1: Copy the BTM jars

Copy the following jars from the BTM distribution to the Tomcat lib/ directory:

You will also need to copy your JDBC driver's JAR file in that same folder. In this example, we've used Derby so we copied derby.jar in Tomcat's lib/ directory.

Step 2: Configure BTM as the transaction manager

Windows: Create a file named setenv.bat with the following commands under Tomcat's bin/ directory:

set CATALINA_OPTS=-Dbtm.root=%CATALINA_HOME%\conf\

Unix: Create a file named with the following commands under Tomcat's bin/ directory:


Now create a file named with the following properties under Tomcat's conf/ directory:${btm.root}/work/btm1.tlog${btm.root}/work/btm2.tlog${btm.root}/conf/

Then edit the file named server.xml under Tomcat's conf/ directory. Under this line:

<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />

add this one:

<Listener className="" />

The <Listener> tag will make sure BTM is started when Tomcat starts up and shutdown when Tomcat shuts down.

The next step is to edit the file named context.xml under Tomcat's conf/ directory. Under this line:


add this one:

<Transaction factory="" />

The <Transaction> tag will bind the transaction manager at the standard JNDI location java:comp/UserTransaction.

Finally, create an empty file named under Tomcat's conf/ directory.

Step 3: Configure datasources that are transaction aware

You have to put your datasources configurations in Tomcat's conf/ file. Here's an example of using BTM with a DataSource that implements javax.sql.XADataSource:


This will create a that implements javax.sql.DataSource and interacts with the javax.sql.XADataSource provided in this instance by Derby.

If your database vendor does not provide an XADataSource, you can use BTM's as the XADataSource to allow your database connections to be controlled by the transaction manager:

Again, we've used Derby as an example, but as the LrcXADataSource uses only the class name and url of a java.sql.Driver, you can use it with any database providing a JDBC driver.

Step 4: Configure transaction manager and datasources initialization in your META-INF/context.xml

In the web application where you want one or more datasource to be used, you have to create a META-INF/context.xml file.


    <Resource name="jdbc/mydatasource" auth="Container" type="javax.sql.DataSource"
        factory="" uniqueName="jdbc/mydatasource" />

    <Resource name="jdbc/exampleNonXADS" auth="Container" type="javax.sql.DataSource"
        factory="" uniqueName="jdbc/exampleNonXADS" />


The <Resource> tags will bind a object each, passing it a javax.naming.Reference containing a javax.naming.StringRefAddr containing the datasource's uniqueName as addrType.

This mechanism is internal to Tomcat. You do not have to worry about how it works, the class will handle those details.

The class will return the datasource previously configured in in Tomcat's conf/ with the specified uniqueName when it is fetched from JNDI.

Step 5: Configure datasources references in your web.xml

Before your code can access configured datasources via JNDI ENC URLs, you need to declare resource references in your web.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
	"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"



Now you can do JNDI lookups on those URLs to access the configured datasources:

DataSource exampleNonXADS = (DataSource) ctx.lookup("java:comp/env/jdbc/exampleNonXADS");
DataSource mydatasource = (DataSource) ctx.lookup("java:comp/env/jdbc/mydatasource");

and you can do JNDI lookups on this URL to access the transaction manager:

UserTransaction ut = (UserTransaction) ctx.lookup("java:comp/UserTransaction");