springboot Consider using absolute ordering.

mvn clean 一下解决了问题，

网上说的修改web.xml中，但是springboot项目中，已经不存在web.xml了。

This error seems to happen after project's spring framework update, clearing the project history file in tomcat webapps may solve the problem.

mvn dependency:tree -Dverbose -Dincludes=groupId:artifactId

A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/chapter17]]
at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:191)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1243)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:829)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1707)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1697)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:835)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/chapter17]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
... 6 more
Caused by: java.lang.IllegalArgumentException: More than one fragment with the name [spring_web] was found. This is not legal with relative ordering. See section 8.2.2 2c of the Servlet specification for details. Consider using absolute ordering.
at org.apache.catalina.deploy.WebXml.orderWebFragments(WebXml.java:2338)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1268)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:881)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:388)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5606)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
... 6 more