This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Excluding a URL for a filter, i believe is not possible. You will have to include all other possible URL patterns. Or one cheeky approach would be include /* for your filter and to code another dummy filter (that does nothing) and map /s/* to it.