启动tomcat4时，提示：组件类型“web-app”未被声明，请问怎么解决？

Question

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE web-app PUBLIC
  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
</web-app>你好像掉了结束的那个标签
是对XML文件结构的不理解造成的吗？你试试，要不就直接用
<?xml version="1.0" encoding="ISO-8859-1" ?>
<web-app>
</web-app>

Answer 1

我只是在提问中复制了头部那一段，实际上下面这段没复制上来而已：
<servlet> <servlet-name> action </servlet-name>
<servlet-class> org.apache.struts.action.ActionServlet </servlet-class>
<init-param> <param-name> application </param-name>
<param-value> Application Resources </param-value> </init-param>
<init-param> <param-name> config </param-name>
<param-value> /WEB-INF/struts-config.xml </param-value> </init-param>
<init-param> <param-name> debug </param-name>
<param-value> 2 </param-value> </init-param>
<init-param> <param-name> detail </param-name>
<param-value> 2 </param-value> </init-param>
<init-param> <param-name> validate </param-name>
<param-value> true </param-value> </init-param>
<load-on-startup> 2 </load-on-startup> </servlet>
<servlet-mapping> <servlet-name> action </servlet-name>
<url-pattern> *.do </url-pattern> </servlet-mapping>
<welcome-file-list> 
<welcome-file> MyJsp.jsp </welcome-file> </welcome-file-list>
<taglib> <taglib-uri> /WEB-INF/struts-bean.tld </taglib-uri>
<taglib-location> /WEB-INF/struts-bean.tld </taglib-location> </taglib>
<taglib> <taglib-uri> /WEB-INF/struts-html.tld </taglib-uri>
<taglib-location> /WEB-INF/struts-html.tld </taglib-location> </taglib>
<taglib> <taglib-uri> /WEB-INF/struts-logic.tld </taglib-uri>
<taglib-location> /WEB-INF/struts-logic.tld </taglib-location> </taglib>
<taglib> <taglib-uri> /WEB-INF/struts-template.tld </taglib-uri>
<taglib-location> /WEB-INF/struts-template.tld </taglib-location> </taglib>
</web-app>

Answer 2

我将web.xml和struts-config.xml都改回myclipse3.8.2初始的文件还是这样。
初始web.xml文件内容如下：
<?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">
   <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>
      <init-param>
         <param-name>debug</param-name>
         <param-value>3</param-value>
      </init-param>
      <init-param>
         <param-name>detail</param-name>
         <param-value>3</param-value>
      </init-param>
      <load-on-startup>0</load-on-startup>
   </servlet>
   <servlet-mapping>
      <servlet-name>action</servlet-name>
      <url-pattern>*.do</url-pattern>
   </servlet-mapping>
</web-app>