Servlet/JSP Spec Apache Tomcat version Actual release revision Minimum Java Version
3.0/2.2 7.0.x 7.0.21 1.6
2.5/2.1 6.0.x 6.0.33 1.5
2.4/2.0 5.5.x 5.5.33 1.4
2.3/1.2 4.1.x (archived) 4.1.40 (archived) 1.3
2.2/1.1 3.3.x (archived) 3.3.2 (archived) 1.1
tomcat 7 新特性
Apache Tomcat 7.x is the current focus of development. It builds upon the improvements made in Tomcat 6.0.x and implements the Servlet 3.0, JSP 2.2 and EL 2.2 specifications. In addition to that, it includes the following improvements:
Web application memory leak detection and prevention（Web应用内存泄漏的探测和预防）
Improved security for the Manager and Host Manager applications
Generic CSRF protection（CSS攻击防护）
Support for including external content directly in a web application
Refactoring (connectors, lifecycle) and lots of internal code clean-up（重构净化很多代码）
参考：http://tomcat.apache.org/whichversion.html