idea 运行多模块Maven项目时，用本地tomcat 7.0+ 部署，报错，如下：

org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/server]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:1017)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:993)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
	at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:712)
	at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:2003)
	at java.util.concurrent.Executors$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.LinkageError: loader constraint violation: loader (instance of org/apache/catalina/loader/WebappClassLoader) previously initiated loading for a different type with name "javax/servlet/ServletContext"
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
	at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:1426)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1897)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1771)
	at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:162)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5669)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 10 more

能找到的解决办法，都尝试了，并没有用
尝试过的解决办法，都未解决问题：
1、pom里添加以下配置，修改成不同的javax.servlet-api版本号，并没有用

<dependency>
	<groupId>javax.servlet</groupId>
	<artifactId>javax.servlet-api</artifactId>
	<version>3.1.0</version>
	<scope>provided</scope>
</dependency>

2、javax.servlet-api包放到tomcat lib目录下

3、修改tomcat配置

tomcat.util.scan.DefaultJarScanner.jarsToSkip=\*
org.apache.catalina.startup.ContextConfig.jarsToSkip=*.jar

于是就尝试更换tomcat，换成 8.5.42 ，这次竟然可以了，成功运行起来了，tomcat 配置如下