我刚刚在ubuntu上使用openjdk 7安装了tomcat 8，但是当访问localhost：8080时，它显示一个空白页面，显示没有错误，只显示空白页面。
我在这里附加了日志错误
18-Feb-2018 08:53:45.302 SEVERE [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Error deploying web application directory /var/lib/tomcat8/webapps/ROOT
java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:729)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1091)
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1830)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
18-Feb-2018 08:53:45.304 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /var/lib/tomcat8/webapps/ROOT has finished in 1,269 ms
18-Feb-2018 08:53:45.318 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
18-Feb-2018 08:53:45.323 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 1334 ms