把struts目录lib下的jar包复制到WebContent/WEB-INF/lib目录，eclipse自动把所有WebContent/WEB-INF/lib目录下的jar包添加到build path里，不必手动添加。在配置web.xml时，
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cvc-complex-type.2.4.a: Invalid content was found starting with element 'taglib'. One of '{"http://java.sun.com/xml/ns/j2ee":description, "http://java.sun.com/xml/ns/j2ee":display-name, "http://java.sun.com/xml/ns/j2ee":icon, "http://java.sun.com/xml/ns/j2ee":distributable, "http://java.sun.com/xml/ns/j2ee":context-param, "http://java.sun.com/xml/ns/j2ee":filter, "http://java.sun.com/xml/ns/j2ee":filter-mapping, "http://java.sun.com/xml/ns/j2ee":listener, "http://java.sun.com/xml/ns/j2ee":servlet, "http://java.sun.com/xml/ns/j2ee":servlet-mapping, "http://java.sun.com/xml/ns/j2ee":session-config, "http://java.sun.com/xml/ns/j2ee":mime-mapping, "http://java.sun.com/xml/ns/j2ee":welcome-file-list, "http://java.sun.com/xml/ns/j2ee":error-page, "http://java.sun.com/xml/ns/j2ee":jsp-config, "http://java.sun.com/xml/ns/j2ee":security-constraint, "http://java.sun.com/xml/ns/j2ee":login-config, "http://java.sun.com/xml/ns/j2ee":security-role, "http://java.sun.com/xml/ns/j2ee":env-entry, "http://java.sun.com/xml/ns/j2ee":ejb-ref, "http://java.sun.com/xml/ns/j2ee":ejb-local-ref, "http://java.sun.com/xml/ns/j2ee":service-ref, "http://java.sun.com/xml/ns/j2ee":resource-ref, "http://java.sun.com/xml/ns/j2ee":resource-env-ref, "http://java.sun.com/xml/ns/j2ee":message-destination-ref, "http://java.sun.com/xml/ns/j2ee":message-destination, "http://java.sun.com/xml/ns/j2ee":locale-encoding-mapping-list}' is expected.
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问题出在web.xml里：
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
第一种方法：
删除xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"即可.
第二种方法：
保留不变，把taglib标签用jsp-config标签包括起来，一样不会提示错误。
在jsp2.0中,且2.4版的DTD验证中,初步估计是由于eclipse在部署时,未对web.xml进行一些校验,而jbuilder则进行了校验,并除非不合法的描述符,而taglib描述符,正确写法是放到
相信是一样的原因。eclipse3.2开始也对web.xml做校验，所以提示错误。在eclipse3.1.2里没有提示错误。