Create a jTDS connection string

As detailed in the jTDS Frequenlty Asked Questions, the URL format for jTDS is:

jdbc:jtds:<server_type>://<server>[:<port>][/<database>][;<property>=<value>[;...]]

So, to connect to a database called "Blog" hosted by a MS SQL Server running on MYPC, you may end up with something like this:

jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS;user=sa;password=s3cr3t

Or, if you prefer to use getConnection(url, "sa", "s3cr3t"):

jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS

EDIT: Regarding your Connection refused error, double check that you're running SQL Server on port 1433, that the service is running and that you don't have a firewall blocking incoming connections.

Really, really, really check if the TCP/IP protocol is enabled in your local SQLEXPRESS instance.

Follow these steps to make sure:

• Open "Sql Server Configuration Manager" in "Start Menu\Programs\Microsoft SQL Server 2012\Configuration Tools\"
• Expand "SQL Server Network Configuration"
• Go in "Protocols for SQLEXPRESS"
• Enable TCP/IP

If you have any problem, check this blog post for details, as it contains screenshots and much more info.

Also check if the "SQL Server Browser" windows service is activated and running:

• Go to Control Panel -> Administrative Tools -> Services
• Open "SQL Server Browser" service and enable it (make it manual or automatic, depends on your needs)
• Start it.

That's it.

After I installed a fresh local SQLExpress, all I had to do was to enable TCP/IP and start the SQL Server Browser service.

Below a code I use to test the SQLEXPRESS local connection. Of course, you should change the IP, DatabaseName and user/password as needed.:

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

public class JtdsSqlExpressInstanceConnect {
    public static void main(String[] args) throws SQLException {
        Connection conn = null;
        ResultSet rs = null;
        String url = "jdbc:jtds:sqlserver://127.0.0.1;instance=SQLEXPRESS;DatabaseName=master";
        String driver = "net.sourceforge.jtds.jdbc.Driver";
        String userName = "user";
        String password = "password";
        try {
            Class.forName(driver);
            conn = DriverManager.getConnection(url, userName, password);
            System.out.println("Connected to the database!!! Getting table list...");
            DatabaseMetaData dbm = conn.getMetaData();
            rs = dbm.getTables(null, null, "%", new String[] { "TABLE" });
            while (rs.next()) { System.out.println(rs.getString("TABLE_NAME")); }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            conn.close();
            rs.close();
        }
    }
}

And if you use Maven, add this to your pom.xml:

<dependency>
    <groupId>net.sourceforge.jtds</groupId>
    <artifactId>jtds</artifactId>
    <version>1.2.4</version>
</dependency>

jdbc:jtds:sqlserver://x.x.x.x/database replacing x.x.x.x with the IP or hostname of your SQL Server machine.

jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS

or

jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS

If you are wanting to set the username and password in the connection string too instead of against a connection object separately:

jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS;user=foo;password=bar

(Updated my incorrect information and add reference to the instance syntax)

A shot in the dark, but From the looks of your error message, it seems that either the sqlserver instance is not running on port 1433 or something is blocking the requests to that port