| Servlet Spec | JSP Spec | EL Spec | WebSocket Spec | JASPIC Spec | Apache Tomcat version | Actual release revision | Supported Java Versions |
|---|---|---|---|---|---|---|---|
| 4.0 | TBD (2.4?) | TBD (3.1?) | TBD (1.2?) | 1.1 | 9.0.x | 9.0.0.M11 (alpha) | 8 and later |
| 3.1 | 2.3 | 3.0 | 1.1 | 1.1 | 8.5.x | 8.5.6 | 7 and later |
| 3.1 | 2.3 | 3.0 | 1.1 | N/A | 8.0.x (superseded) | 8.0.38 (superseded) | 7 and later |
| 3.0 | 2.2 | 2.2 | 1.1 | N/A | 7.0.x | 7.0.72 | 6 and later (7 and later for WebSocket) |
| 2.5 | 2.1 | 2.1 | N/A | N/A | 6.0.x | 6.0.47 | 5 and later |
| 2.4 | 2.0 | N/A | N/A | N/A | 5.5.x (archived) | 5.5.36 (archived) | 1.4 and later |
| 2.3 | 1.2 | N/A | N/A | N/A | 4.1.x (archived) | 4.1.40 (archived) | 1.3 and later |
| 2.2 | 1.1 | N/A | N/A | N/A | 3.3.x (archived) | 3.3.2 (archived) | 1.1 and later |
来源：http://tomcat.apache.org/whichversion.html
web.xml示例：
http://www.mkyong.com/web-development/the-web-xml-deployment-descriptor-examples/
or
http://blog.csdn.net/ceclar123/article/details/38173755