转载一个Tomcat错误分析

Tomcat 4.1中出现的错误一例

SEVERE: Parse Error at line 5 column 19: Document root element "web-app", must match DOCTYPE root "null".
org.xml.sax.SAXParseException: Document root element "web-app", must match DOCTYPE root "null".

SEVERE: Parse Error at line 5 column 19: Document is invalid: no grammar found.
org.xml.sax.SAXParseException: Document is invalid: no grammar found.

偶用的是Tomcat 4.1.24+MyEclipse，结果在新建一个项目中出现了如上问题，郁闷了好久，查阅资料若干，最后总结如下：

我到网路上查，看见说是Tomcat 4.xx should use the 2.3 DTD spec ,If you're using the 2.4 spec, you'll need Tomcat 5.
确实web.xml中用的是2.4 spec。

-- ---- ---- ---- ---- ---- --
org.apache.commons.digester.Digester error SEVERE: Parse Error at line 6
column 19: Document root element "taglib ", must match DOCTYPE root "null ".
org.xml.sax.SAXParseException: Document root element "taglib ", must match
DOCTYPE root "null ".
-- ---- ---- ---- ---- ---- --
So, I tryed finding the error looking through the tld files, googling a bit
and so on, until I tryed removing the jstl.jar and standard.jar from my
web-applications. Suddenly no error was reported.
结论：Tomcat4.1.24中是Servlet2.3规范，不支持2.4规范，因此如果在项目中添加了jstl.jar或者项目的web.xml中出现2.4规范，就会报如上的错误

转载自：http://blog.java-cn.com/user1/5023/archives/2005/23365.html