I used that at work, but it's the weekend and I don't have that code here. But no problem, I just googled "sql server 2005 jdbc url" and the first link has the answer:
http://msdn2.microsoft.com/en-us/library/ms378428.aspx
You could try that too the next time you have a question. It's amazing how often you find the answer.
The connection URL for the default SQL Server 2005 database is jdbc:sqlserver://localhost:<port>.
<port> is obtained from the SQL Server Configuration Manager. To obtain the <port>, select SQL Server 2005 Network Configuration > Protocols for SQLEXPRESS in SQL Server Configuration Manager. Right-click the TCP/IP node, and select Properties. Select the IP Addresses tab in the TCP/IP dialog. In the IP ALL section, the TCP Dynamic Ports specifies the <port> value