public static boolean probarConexion(String url,String user , String pass){
        java.sql.Connection con = null;      
        try {
           Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            con = java.sql.DriverManager.getConnection(url, user, pass);
            if (con != null) {
                return true;
            }
        } catch (ClassNotFoundException | SQLException e) {
            return false;
        }
        return false;
    }