tomcat无法解压war包，eclipse可以导入运行，tomcat异常如下：
java.net.UnknownHostException: java.sun.com
  at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:177)
  at java.net.Socket.connect(Socket.java:519)
  at java.net.Socket.connect(Socket.java:469)
  at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
  at sun.net.www.http.HttpClient.openServer(HttpClient.java:382)
  at sun.net.www.http.HttpClient.openServer(HttpClient.java:509)
  at sun.net.www.http.HttpClient.<init>(HttpClient.java:231)
  at sun.net.www.http.HttpClient.New(HttpClient.java:304)
  at sun.net.www.http.HttpClient.New(HttpClient.java:316)
  at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLC
onnection.java:817)
  at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConne
ction.java:769)
  at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection
.java:694)
  at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLCon
nection.java:938)
  at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrent
Entity(XMLEntityManager.java:973)
  at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startEntity(
XMLEntityManager.java:905)
  at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startDTDEnti
ty(XMLEntityManager.java:872)
  at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.setInputSou
rce(XMLDTDScannerImpl.java:282)
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDis
patcher.dispatch(XMLDocumentScannerImpl.java:1021)
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImp
l.scanDocument(XMLDocumentFragmentScannerImpl.java:368)
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(X
ML11Configuration.java:834)
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(X
ML11Configuration.java:764)
  at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.
java:148)
  at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Ab
stractSAXParser.java:1242)
  at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1626)
  at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.ja
va:631)
  at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.j
ava:601)
  at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502
)
  at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
  at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java
:324)
  at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:142)
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)

  at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)

  at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463
)
  at org.apache.catalina.core.StandardService.start(StandardService.java:5
25)
  at org.apache.catalina.core.StandardServer.start(StandardServer.java:754
)
  at org.apache.catalina.startup.Catalina.start(Catalina.java:595)