Apache-Tomcat的整合---什么是JK
Apache-Tomcat的整合---什么是JK

JK is a replacement to the elderly mod_jserv. It was a completely new Tomcat-Apache plug-in that handles the communication between Tomcat and Apache.
JK2 is a refactoring of JK . The native part has been completly restructured and the configuration has been simplified a lot.
mod_jk is an Apache module to be used with Apache 1.3 and 2.0 Webservers. isapi is a redirector to be used with IIS . nsapi is a redirector to be used with Netscape/iPlanet . dsapi is a redirector to to be used with Domino .

mod_jserv .
mod_jserv was too complex and because it was ported from Apache/JServ, it brought with it lots of JServ specific bits that aren't needed by Apache.
mod_jserv supported only Apache webservers on Unix OS, JK supports much more web servers and operating systems through via a compatibility layer named the JK library . The layered approach provided by the JK library makes it easier to support many different webservers and OS.
3.2.x , 3.3.x , 4.0.x , 4.1.x and 5.x


mod_webapp documentation.
webapp site for it and then decide if you want to go on reading.
mod_webapp is that is very easy to configure, has a well defined protocol named WARP , does not care about the old crappy protocols used in Tomcat-3.x and so. But it would be possible to implement the WARP protocol in JK2 ;-))
Apache Portable Runtime which is still only easily available via Apache 2.0 and that it didn't support webservers like IIS, NES/iPlanet or Domino.