标签在web.xml文件中报错解决方法

文章引用ITEYE网站博主jeelee的文章

配置web.xml文件时，taglib标签报错，但不会影响程序的运行，web.xml 如下：

 
<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"> 
    <display-name>testSitemeshdisplay-name> 
    <filter> 
        <filter-name>sitemeshfilter-name> 
        <filter-class>com.opensymphony.module.sitemesh.filter.PageFilterfilter-class> 
    filter> 
    <filter-mapping> 
        <filter-name>sitemeshfilter-name> 
        <url-pattern>/*url-pattern> 
    filter-mapping> 
    <taglib> 
        <taglib-uri>sitemesh-decoratortaglib-uri> 
        <taglib-location>/WEB-INF/sitemesh-decorator.tldtaglib-location> 
    taglib> 
    <taglib> 
        <taglib-uri>sitemesh-pagetaglib-uri> 
        <taglib-location>/WEB-INF/sitemesh-page.tldtaglib-location> 
    taglib> 
    <welcome-file-list> 
        <welcome-file>index.jspwelcome-file> 
    welcome-file-list> 
web-app> 

其中的taglib标签加入后，eclipse报错，内容如下：

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. 

解决方法有两个：

1、把

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">

这句改成

<web-app > 

解 释：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,正确写法是放到描述符 中。

2、在taglib外面加个jsp-config标签：

<jsp-config> 
  <taglib> 
    <taglib> 
        <taglib-uri>sitemesh-decorator</taglib-uri> 
        <taglib-location>/WEB-INF/sitemesh-decorator.tld</taglib-location> 
    </taglib> 
    <taglib> 
        <taglib-uri>sitemesh-page</taglib-uri> 
        <taglib-location>/WEB-INF/sitemesh-page.tld</taglib-location> 
    </taglib> 
</jsp-config> 

标签使用详解：
包括 和两个子元素。

其中元素在JSP 1.2时就已经存在；而是JSP 2.0 新增的元素。
元素主要有八个子元素，它们分别为：
1.：设定的说明；
2.：设定名称；
3.：设定值所影响的范围，如：/CH2 或 /*.jsp；
4.：若为true，表示不支持EL 语法；
5.：若为true，表示不支持<% scripting %>语法；
6.：设定JSP 网页的编码；
7.：设置JSP 网页的抬头，扩展名为.jspf；
8.：设置JSP 网页的结尾，扩展名为.jspf。