（XF - 4）zk 应用之间访问
How to access resources in another application
1.Let us assume you have another application called app2. Then, you can access the resource by use of "~app2/your/resource/path".
For example,
<include src="~app2/main/foo.zul"/>
Notice that the Web container might prevent you from accessing other Web applications. In this case, org.zkoss.lang.SystemException(("Context not found or not visible to....") will be thrown. To enable it you have to configure the Web container properly.
2.In context.xml, specify crossContext="true" to the Context element:
<Context crossContext="true">
