how can I connect to sqlserver express

if I use -> jdbc:sqlserver://localhost//SQLEXPRESS;databaseName=Rabbit;

Warning : The TCP/IP connection to the host has failed. java.net.UnknownHostException

if I use -> jdbc:sqlserver://localhost;databaseName=Rabbit;

Warning : Timeout

thank and regard.

This error occurres when the database does not respond within a give time frame. My guess is that you need to add the port as localhost:<port> - whatever the port is for your db.