xxxt.tld", see JSP 2.2 specification section 7.3.1 for more details

错误描述

在jsp页面引入了自定义的TLD文件的时候，碰到了一个错误

Invalid tld file: "/WEB-INF/tags/xxxt.tld", see JSP 2.2 specification section 7.3.1 for more details

错误原因

不符合 JSP2.2 中对tags的规定。
规定说的是这个：

In the jsp-2_2

JSP.7.3.1 Identifying Tag Library Descriptors Tag library descriptor files have names that use the extension .tld, and the extension indicates a tag library descriptor file. When deployed inside a JAR file, the tag library descriptor files must be in the META-INF directory, or a subdirectory of it. When deployed directly into a web application, the tag library descriptor files must always be in the WEB-INF directory, or some subdirectory of it. TLD files should not be placed in /WEB-INF/classes or /WEB-INF/lib, and must not be placed inside /WEB-INF/tags or a subdirectory of it, unless named implicit.tld and intended to configure an implicit tag library with its JSP version and tlib-version.

the .tld file can't be in classes , lib ,tags folder or subfolder.

意思是说，如果你使用的是jsp2.2就不能把tld文件放在 /WEB-INF/tags 以及其子目录下。
jsp版本和tomcat的版本是相关的。jsp版本和tomcat的版本对应关系如下：

Servlet Spec	JSP Spec	EL Spec	WebSocket Spec	JASPIC Spec	Apache Tomcat Version	Latest Released Version	Supported Java Versions
4.0	2.3	3.0	1.1	1.1	9.0.x	9.0.1 (beta)	8 and later
3.1	2.3	3.0	1.1	1.1	8.5.x	8.5.23	7 and later
3.1	2.3	3.0	1.1	N/A	8.0.x (superseded)	8.0.47 (superseded)	7 and later
3.0	2.2	2.2	1.1	N/A	7.0.x	7.0.82	6 and later(7 and later for WebSocket)
2.5	2.1	2.1	N/A	N/A	6.0.x (archived)	6.0.53 (archived)	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