写servlet时碰到的疑惑？

Question

改成这样：
<web-app>
  <servlet>
    <servlet-name>CookieServlet</servlet-name>
    <servlet-class>
   CookieServlet
    </servlet-class>
  </servlet>  <servlet>
    <servlet-name>HelloServlet</servlet-name>
    <servlet-class>
   HelloServlet
    </servlet-class>
  </servlet>  <servlet-mapping>
    <servlet-name>CookieServlet</servlet-name>
    <url-pattern>/CookieServlet</url-pattern>
  </servlet-mapping>  <servlet-mapping>
    <servlet-name>HelloServlet</servlet-name>
    <url-pattern>/HelloServlet</url-pattern>
  </servlet-mapping>
</web-app>web.xml要按以下顺序写：
icon
display-name
description
distributable
context-param
servlet
servlet-mapping
session-config
mime-mapping
welcome-file-list
error-page
taglib
resource-ref
security-constraint
login-config
security-role
env-entry
ejb-ref