多文件Form上传，配置了忽略空文件的情况下，引发的异常

[albinhdk]

org.nutz.castor.FailToCastObjectException: Fail to cast from <java.lang.String> to <org.nutz.mvc.upload.TempFile> for {} because:
BorningException:Fail to born 'org.nutz.mvc.upload.TempFile'
by args: [
@()]
at org.nutz.castor.Castors.cast(Castors.java:258)
at org.nutz.castor.Castors.castTo(Castors.java:320)
at org.nutz.castor.castor.Collection2Object.cast(Collection2Object.java:17)
at org.nutz.castor.castor.Collection2Object.cast(Collection2Object.java:1)
at org.nutz.castor.Castors.cast(Castors.java:252)
at org.nutz.castor.Castors.castTo(Castors.java:320)
at org.nutz.mvc.adaptor.injector.ArrayInjector.convertMe(ArrayInjector.java:63)
at org.nutz.mvc.adaptor.injector.ArrayInjector.get(ArrayInjector.java:42)
at org.nutz.mvc.adaptor.AbstractAdaptor.adapt(AbstractAdaptor.java:242)
at org.nutz.mvc.upload.UploadAdaptor.adapt(UploadAdaptor.java:117)
at org.nutz.mvc.impl.processor.AdaptorProcessor.process(AdaptorProcessor.java:28)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ActionFiltersProcessor.process(ActionFiltersProcessor.java:40)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.integration.shiro.NutShiroProcessor.process(NutShiroProcessor.java:51)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ModuleProcessor.process(ModuleProcessor.java:113)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.EncodingProcessor.process(EncodingProcessor.java:27)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.UpdateRequestAttributesProcessor.process(UpdateRequestAttributesProcessor.java:15)
at org.nutz.mvc.impl.NutActionChain.doChain(NutActionChain.java:40)
at org.nutz.mvc.impl.ActionInvoker.invoke(ActionInvoker.java:67)
at org.nutz.mvc.ActionHandler.handle(ActionHandler.java:31)
at org.nutz.mvc.NutFilter.doFilter(NutFilter.java:183)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:124)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

form中有多个的情况下
后台ioc方式配置了上传参数如下：
//文件池
.....
fields : {
// 是否忽略空文件, 默认为 false
ignoreNull : true,
......

[wendal]

方法参数 @param("file")TempFile[] files