spring 中 web.xml的<welcome-file-list>与<error-page>错误

web.xml内容如下:
 
  <?xml version="1.0" encoding="UTF-8"?>
  <!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>
  <context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>/WEB-INF/smtt-servlet.xml</param-value>
  </context-param>
 
  <listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
 
  <servlet>
  <servlet-name>smtt</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  <servlet-name>smtt</servlet-name>
  <url-pattern>*.htm</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
  <welcome-file>/default.htm</welcome-file>
  </welcome-file-list>
  <error-page>
  <error-code>404</error-code>
  <location>/404.htm</location>
  </error-page>
  <error-page>
  <error-code>500</error-code>
  <location>/500.htm</location>
  </error-page>
  </web-app>
 
 
  其中default.htm,404.htm,500.htm在smtt-servlet.xml影射处理如下:
  <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
  <property name="mappings">
  <props>
  <prop key="/default.htm">defaultPageController</prop>
  <prop key="/404.htm">error404Controller</prop>
  <prop key="/500.htm">error500Controller</prop>
  </props>
  </property>
  </bean>
 
  现象:
  在smtt部署成功后,输入URL:http://localhost:8080/smtt/并不会自动进入default.htm,发生404(500)错误也不会转到404.htm(500.htm).但这些地址都是有效的,都可以请求到正确数据的.   
  问题:   
  这是怎么回事?如何解决?

------解决方法--------------------------------------------------------
<welcome-file-list>
  <welcome-file>default.htm</welcome-file>
  </welcome-file-list>
------解决方法--------------------------------------------------------
web.xml中的只能是实际存在的html或jsp文件。