spring boot 를 war로 생성하여 tomcat 서버에 올렸을 때 발생되는 오류

tomcat 구동시 아래와 같은 오류가 발생되면 tomcat 버전을  최신으로 설치해 보시기 바랍니다.

(tomcat 다운로드 링크)

 

아마도 tomcat/lib 에 있는 servlet-api.jar 파일 구 버전으로 인해 호환이 안되거나 파일이 없는 것 같습니다.
참고로 필자는 tomcat 9.0 으로 설치 후 잘 동작되는 것을 확인하였습니다.

rg.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/sss]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1092)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1984)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NoClassDefFoundError: javax/servlet/GenericFilter
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:3205)
        at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:1373)
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1861)
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
        at org.apache.tomcat.websocket.server.WsServerContainer.<init>(WsServerContainer.java:106)
        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:5623)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
        ... 10 more
Caused by: java.lang.ClassNotFoundException: javax.servlet.GenericFilter
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1892)
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
        ... 22 more