java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderListener

解决办法：

1.项目右键Properties

2.搜索Deployment Assembly

3.点击add

4.选择Java Build Path Entries

5.点击next 选择Maven Dependencies 点击Finish

6.点击Apply and Close

创建一个maven项目时启动项目控制台抛出了错误信息：

严重: Error configuring application listener of class org.springframework.web.context.ContextLoaderListener
java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderListener
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
	at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:509)
	at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:490)
	at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4775)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5314)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
十二月 05, 2020 2:05:36 下午 org.apache.catalina.core.StandardContext listenerStart
严重: Error configuring application listener of class org.springframework.web.util.IntrospectorCleanupListener
java.lang.ClassNotFoundException: org.springframework.web.util.IntrospectorCleanupListener
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
	at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:509)
	at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:490)
	at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4775)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5314)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
十二月 05, 2020 2:05:36 下午 org.apache.catalina.core.StandardContext listenerStart
严重: Skipped installing application listeners due to previous error(s)
十二月 05, 2020 2:05:36 下午 org.apache.catalina.core.StandardContext startInternal
严重: One or more listeners failed to start. Full details will be found in the appropriate container log file
十二月 05, 2020 2:05:36 下午 org.apache.catalina.core.StandardContext startInternal
严重: Context [/MyDemo] startup failed due to previous errors
十二月 05, 2020 2:05:36 下午 org.apache.coyote.AbstractProtocol start
信息: Starting ProtocolHandler ["http-nio-8080"]
十二月 05, 2020 2:05:36 下午 org.apache.coyote.AbstractProtocol start
信息: Starting ProtocolHandler ["ajp-nio-8009"]
十二月 05, 2020 2:05:36 下午 org.apache.catalina.startup.Catalina start
信息: Server startup in 733 ms

　

 但是发现maven的依赖包都是下载了的，于是又找其他的问题。