问题简介：
系统win s 2016
用的：tomcat8.5
应用：javaweb
问题：javaweb做的网站应用，用servlet上传图片或文件时，tomcat出现以下异常，导致用户上传图片或文件上传不上去，这个问题在重庆tomcat后得到恢复，有时连续几小时不出现问题，可以成功上传，有时就突然出现下面异常。请教各位大神这怎么搞？是tomcat本身问题，还是服务器防火墙的问题，服务器防火墙已经全部关闭，还是路由器防火墙的问题，路由器防火墙也全部关闭！
下面是tomcat异常代码！
org.apache.commons.fileupload.FileUploadBase$IOFileUploadException: Processing of multipart/form-data request failed. 指定的 网络名不再可用。
at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:367)
at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:126)
at com.ringtech.util.UpSeeking.doGet(UpSeeking.java:72)
at com.ringtech.util.UpSeeking.doPost(UpSeeking.java:168)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
at org.apache.tomcat.util.net.Nio2Endpoint$SocketProcessor.doRun(Nio2Endpoint.java:1688)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at org.apache.tomcat.util.net.AbstractEndpoint.processSocket(AbstractEndpoint.java:1051)
at org.apache.tomcat.util.net.Nio2Endpoint$Nio2SocketWrapper$4.completed(Nio2Endpoint.java:636)
at org.apache.tomcat.util.net.Nio2Endpoint$Nio2SocketWrapper$4.completed(Nio2Endpoint.java:614)
at sun.nio.ch.Invoker.invokeUnchecked(Unknown Source)
at sun.nio.ch.Invoker.invokeUnchecked(Unknown Source)
at sun.nio.ch.WindowsAsynchronousSocketChannelImpl$ReadTask.completed(Unknown Source)
at sun.nio.ch.Iocp$EventHandlerTask.run(Unknown Source)
at sun.nio.ch.AsynchronousChannelGroupImpl$1.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: 指定的网络名不再可用。
at sun.nio.ch.Iocp.translateErrorToIOException(Unknown Source)
at sun.nio.ch.Iocp.access$700(Unknown Source)
... 5 more
