同一个tomcat下两个项目分别配置单独的域名访问，遇到重复加载有关问题

同一个tomcat下两个项目分别配置单独的域名访问，遇到重复加载问题
servel.xml配置如下：

 <Engine name="Catalina" defaultHost="localhost">


    

      <Realm className="org.apache.catalina.realm.LockOutRealm">

        

        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"

               resourceName="UserDatabase"/>

      </Realm>


      <Host name="localhost"  appBase="webapps" unpackWARs="true">


       <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"

               prefix="localhost_access_log." suffix=".txt"

               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

	 </Host>

	  

	  <Host name="www.a.com"  appBase="webapps" unpackWARs="true">


        

        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"

               prefix="localhost_access_log." suffix=".txt"

               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

			   <Context docBase="resource" path=""  reloadable="true" ></Context>

	   </Host>

		  

	 <Host name="www.b.com"  appBase="webapps" unpackWARs="true">


        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"

               prefix="localhost_access_log." suffix=".txt"

               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

			   <Context docBase="BookStore" path=""  reloadable="true" ></Context>

	 </Host>

</Engine>

------解决思路----------------------
appBase是不是不能一样啊...不是要两个路径吗?