Small Servlet Hacks on Franks Internet Playground.

Find here a few small, but maybe handy servlets. If you find s.th. interesting for you, enjoy!

1. Sometimes you need to be backward compatible: The Cgi-Servlet2 lets you run CGI's within a Servlet Environment (successfully used to host the Mailman lists on this page). The code is essentially a mess, but ...
   For jdk's prior to 1.2 (no Collections) use the older CgiServlet. Thank you to David W. Yutzy for pointing out the useless crossreferences to a long gone Util class.
2. Sometimes you need to masquerade s.th., The Proxy Servlet lets you pass thru requests from one HTTP server to another (also successfull to hide a Mailman server). This Servlet is currently acvtive, e.g. HTtp://frank.spieleck.de/reweb/?tab=1&link=1&id=713015&name=dufns shows you (approximately) the same page like http://v1.nedstatbasic.net/s?tab=1&link=1&id=713015&name=dufns. The latter is the Doris & Frank homepage counter and nedstatbasic is on the killfile of my employers squid :-( Currently this is a fixed redirection to a site, one day I'd like to improve that and make a real rewebber from it.
   This proxy servlet is lazy. A real proxy had to rewrite all links in the passed through stream to point to itself. Not done, not currently needed by me, won't happen soon. There once used to be a much more fully featured (but also much heavier) version at tigris.org.
3. Sometimes you need to masquerade a file as s.th. different: The Fetchlet lets you download from a different url, from a different file name and different mime type.
4. Sometimes you need a download via e-Mail The Maillet lets you send a url via e-mail to a mail account.
5. This ultratiny Trampolin Servlet is useful for example if you want to track, which links visitors use to leave your web site: Don't place a link, place an indirect link via the trampolin! E.g. replace links like <A HREF="http://spieleck.de"> with something like <A HREF="YOUR-CONFIGURED-TRAMPOLIN-PATH?http://spieleck.de"> an the you can see in your access.log, how many people use that particular link.
6. The Voting Servlet on the other hand is relatively complex. It implements a very simple vote for your website.
   • Place a test vote!.
   • See test vote result!.
   At least it needs lots of configuration data. Ask me if you need information.
7. Not a Servlet, but a Servlet Spec 2.3 HttpSessionListener which allows a Servlet to look into all Sessions running in the current ServletContext (Application): SessionAccountingListener.java. This class contains some usefull JavaDoc about class usage.
8. Need to make something strange? With the RandomLinkServlet you can forward a visitor to a random link from a set of links you configure.
9. When you are fluent in German, there is more stuff to download in another space of this server, Patrick's Spieleck