为什么web.xml错误
<?xml version= "1.0 " encoding= "UTF-8 "?>
<web-app xmlns= "http://java.sun.com/xml/ns/j2ee " xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance " version= "2.4 " xsi:schemaLocation= "http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd ">
<!-- Standard Action Servlet Configuraction -->
<servlet>
<servlet-name> action </servlet-name>
<servlet-class> org.apache.struts.action.ActionServlet </servlet-class>
<init-param>
<param-name> config </param-name>
<param-value> /WEB-INF/struts-config.xml </param-value>
</init-param>
<load-on-startup> 2 </load-on-startup>
</servlet>
<!-- Standard Action Servlet Mapping -->
<servlet-mapping>
<servlet-name> action </servlet-name>
<url-pattern> *.do </url-pattern>
</servlet-mapping>
<!-- The Usual Welcome File List -->
<welcome-file-list>
<welcome-file> hello.jsp </welcome-file>
</welcome-file-list>
<!-- Struts Tag Library Descriptors -->
<taglib>
<taglib-url> /WEB-INF/tld/struts-bean.tld </taglib-url>
<taglib-location> /WEB-INF/struts-bean.tld </taglib-location>
</taglib>
<taglib>
<taglib-url> /WEB-INF/tld/struts-html.tld </taglib-url>
<taglib-location> /WEB-INF/struts-html.tld </taglib-location>
</taglib>
<taglib>
<taglib-url> /WEB-INF/tld/struts-logic.tld </taglib-url>
<taglib-location> /WEB-INF/struts-logic.tld </taglib-location>
</taglib>
</web-app>
提示这里错误
<taglib>
<taglib-url> /WEB-INF/tld/struts-bean.tld </taglib-url>
<taglib-location> /WEB-INF/struts-bean.tld </taglib-location>
</taglib>
java.lang.IllegalArgumentException: Can 't convert argument: null
at org.apache.tomcat.util.IntrospectionUtils.convert(IntrospectionUtils.java:975)
at org.apache.tomcat.util.digester.CallMethodRule.end(CallMethodRule.java:522)
at org.apache.tomcat.util.digester.Rule.end(Rule.java:228)
at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1057)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:633)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDoc