是别人的项目，但是我用tomcat7.0添加不进去，他说要用8.0然后我换了8.0，就启动不了了，一直报错并且我换成7.0就能启动，8.0以上的版本就启动不了。这是什么问题，求解决，谢谢各位。

错误信息：
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]

at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:915) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) ... 6 more

Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String;

at org.apache.tomcat.websocket.server.WsServerContainer.<init>(WsServerContainer.java:150) at org.apache.tomcat.websocket.server.WsSci.init(WsSci.java:131) at org.apache.tomcat.websocket.server.WsSci.onStartup(WsSci.java:47) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5303) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 6 more 

九月 25, 2016 10:13:52 上午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ass_web]]

at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:915) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ass_web]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) ... 6 more

Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String;

at org.apache.tomcat.websocket.server.WsServerContainer.<init>(WsServerContainer.java:150) at org.apache.tomcat.websocket.server.WsSci.init(WsSci.java:131) at org.apache.tomcat.websocket.server.WsSci.onStartup(WsSci.java:47) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5303) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 6 more 

九月 25, 2016 10:13:52 上午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]

at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:915) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:787) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.startup.Catalina.start(Catalina.java:629) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Caused by: org.apache.catalina.LifecycleException: A child container failed during start

at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:923) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 6 more 

九月 25, 2016 10:13:52 上午 org.apache.catalina.startup.Catalina start
严重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.startup.Catalina.start(Catalina.java:629) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:787) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 7 more

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 9 more

Caused by: org.apache.catalina.LifecycleException: A child container failed during start

at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:923) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 11 more 

九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["http-nio-8080"]
九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["ajp-nio-8009"]
九月 25, 2016 10:13:52 上午 org.apache.catalina.core.StandardService stopInternal
信息: Stopping service Catalina
九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["http-nio-8080"]
九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol destroy
严重: Failed to destroy end point associated with ProtocolHandler ["http-nio-8080"]
java.lang.NullPointerException

at org.apache.tomcat.util.net.NioEndpoint.releaseCaches(NioEndpoint.java:316) at org.apache.tomcat.util.net.NioEndpoint.unbind(NioEndpoint.java:492) at org.apache.tomcat.util.net.AbstractEndpoint.destroy(AbstractEndpoint.java:821) at org.apache.coyote.AbstractProtocol.destroy(AbstractProtocol.java:551) at org.apache.catalina.connector.Connector.destroyInternal(Connector.java:1023) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.core.StandardService.destroyInternal(StandardService.java:589) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.core.StandardServer.destroyInternal(StandardServer.java:877) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.startup.Catalina.start(Catalina.java:633) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485) 

九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["ajp-nio-8009"]
九月 25, 2016 10:13:52 上午 org.apache.coyote.AbstractProtocol destroy
严重: Failed to destroy end point associated with ProtocolHandler ["ajp-nio-8009"]
java.lang.NullPointerException

at org.apache.tomcat.util.net.NioEndpoint.releaseCaches(NioEndpoint.java:316) at org.apache.tomcat.util.net.NioEndpoint.unbind(NioEndpoint.java:492) at org.apache.tomcat.util.net.AbstractEndpoint.destroy(AbstractEndpoint.java:821) at org.apache.coyote.AbstractProtocol.destroy(AbstractProtocol.java:551) at org.apache.catalina.connector.Connector.destroyInternal(Connector.java:1023) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.core.StandardService.destroyInternal(StandardService.java:589) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.core.StandardServer.destroyInternal(StandardServer.java:877) at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:292) at org.apache.catalina.startup.Catalina.start(Catalina.java:633) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)