Can't successfully deploy ext project to 7.x server

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: 3.0.0
• Fix Version/s: None
• Component/s: Servers, Servers > Tomcat
• Labels: None
• Environment: Liferay IDE 3.0.0.201601150527 ; liferay-portal-7.0-ce-b2

Reproduce steps:

1 create ext project
2 deploy to 7.x server

error log in console :

03:04:36,940 ERROR [pool-4-thread-4][com_liferay_portal_wab_extender:96] Unable to load servlet com.liferay.portal.webserver.DynamicResourceServlet
java.lang.ClassNotFoundException: com.liferay.portal.webserver.DynamicResourceServlet cannot be found by dd-ext_7.0.0.1
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:444)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:357)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:349)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:583)
at com.liferay.portal.wab.extender.internal.definition.WebXMLDefinitionLoader._getServletInstance(WebXMLDefinitionLoader.java:357)
at com.liferay.portal.wab.extender.internal.definition.WebXMLDefinitionLoader.endElement(WebXMLDefinitionLoader.java:199)
at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
......

.....

Caused by: D:\WEB-INF\ext-web\docroot does not exist.
at org.apache.tools.ant.types.AbstractFileSet.getDirectoryScanner(AbstractFileSet.java:483)
at org.apache.tools.ant.taskdefs.Copy.execute(Copy.java:475)
at com.liferay.util.ant.CopyTask.copyDirectory(CopyTask.java:67)
at com.liferay.util.ant.CopyTask.copyDirectory(CopyTask.java:85)
at com.liferay.portal.deploy.hot.ExtHotDeployListener.installExt(ExtHotDeployListener.java:222)
at com.liferay.portal.deploy.hot.ExtHotDeployListener.doInvokeDeploy(ExtHotDeployListener.java:165)