In this example we’ll need to add a JDBC Connection Configuration to our test plan. This will define and control the way in which JMeter will access your database.

Notice I’ve left the defaults for connection pool properties, although you may need to tweak this depending on how you’ll access the data. I’ve used a JDBC connection URL that accesses a local mysql server listening on port 3306. The database in use is called watirgrid

I’ve also defined the JDBC Driver class and specified the username / password to connect with.

Now we can make a JDBC request using the JDBC Request sampler. It will look something like this:

The Variable Name matches the JDBC Connection Config Variable Name i.e. mysql

I’m using a select statement that will print out results in a JSON-like format. That query is as follows:

SELECT
CONCAT("[",
GROUP_CONCAT(
CONCAT("{email:'",email,"'"),
CONCAT(",login_count:'",login_count),"'}")
,"]")
AS json FROM users

In doing this, it will return a result set that looks like this:

+-------------------------------------------------+
| json                                            |
+-------------------------------------------------+
| [{email:'tim.koops@gmail.com',login_count:'1'}] |
+-------------------------------------------------+
1 row IN SET (0.00 sec)

Now we need to add a Post Processor Regex Extractor to the JDBC request as follows:

The reason we do this is so we can extract the results from the JSON string returned by the database query. For example, to extract and populate a variable called ${email} our PPRE would look like this:

Now we’re cooking! Add a Debug Sampler to confirm everything works as you’d expect. You should see results like this in the response data

email=tim.koops@gmail.com
email_g=1
email_g0=email:'tim.koops@gmail.com'
email_g1=tim.koops@gmail.com
mysql=org.apache.jmeter.protocol.jdbc.config.DataSourceElement$DataSourceComponentImpl@10d69502

Attached is a demo test plan: jdbc_example.jmx

The next thing to do is copy that file into your LoadRunner /classes subdirectory.

Now edit the run-time settings for your Java Vuser script (F4). You need to add the location of the jar file to your classpath parameters.

At the top of your script, depending on which functionality you end up using, you need to import the relevant packages for your script. I’m currently using the following import statements:

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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.*;

My public class called Actions now initializes a private Connection object called ‘connection’

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private Connection connection;

My init() method will open up a single connection to the database using the following code.

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// Initialize DB connection
	connection = null;
	try {
	    Class.forName("com.mysql.jdbc.Driver").newInstance();
	} catch (Exception ex) {}
	try {
	    connection =  DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?" +
						      "user=myuser&password=mypassword");
	} catch (SQLException e) {}

You may want to handle exceptions a little more thoroughly than me

Now within the action() method, I can make repeated calls to the MySQL database, as each vuser iterates over the code.

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String FORMATTED_MESSAGE = null;
	Statement stmt 	= null;
	ResultSet rs 	= null;
 
	try {
	    stmt = connection.createStatement();
	    rs   = stmt.executeQuery("SELECT xml FROM my_data");
            while (rs.next()) {
		FORMATTED_MESSAGE = rs.getString("xml");
		//lr.message(FORMATTED_MESSAGE);
	    }
	    rs.close();
	    stmt.close();
	} catch (SQLException e) {
	}

In this example I’m populating a string called FORMATTED_MESSAGE with the XML returned from a SQL query.

Putting it all together, your Java Vuser script should look something like this.

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import lrapi.lr;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.*;
 
public class Actions
{
    private Connection connection;
 
    public int init() {
        // Initialize DB connection
        connection = null;
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (Exception ex) {}
        try {
            connection =  DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?" +
                                  "user=myuser&password=mypassword");
        } catch (SQLException e) {}
	    return 0;
    } //end of init
 
    public int action() throws JMSException {
        String FORMATTED_MESSAGE = null;
        Statement stmt 	= null;
        ResultSet rs 	= null;
 
        try {
            stmt = connection.createStatement();
            rs   = stmt.executeQuery("SELECT xml FROM mydata");
            while (rs.next()) {
                FORMATTED_MESSAGE = rs.getString("xml");
                //lr.message(FORMATTED_MESSAGE);
            }
            rs.close();
            stmt.close();
        } catch (SQLException e) {
        }
	    return 0;
    } //end of action
 
    public int end() throws JMSException {
	    connection = null;
        return 0;
    } //end of end
}