idea啓動spring boot時報如下錯誤：
java.lang.IllegalStateException: ApplicationEventMulticaster not initialized - call 'refresh' before multicasting events via the context: org.springframework.context.annotation.AnnotationConfigApplicationContext@65f8f5ae: startup date [Fri Jan 17 09:57:33 CST 2020]; root of context hierarchy
at org.springframework.context.support.AbstractApplicationContext.getApplicationEventMulticaster(AbstractApplicationContext.java:404)
at org.springframework.context.support.ApplicationListenerDetector.postProcessBeforeDestruction(ApplicationListenerDetector.java:97)
at org.springframework.beans.factory.support.DisposableBeanAdapter.destroy(DisposableBeanAdapter.java:253)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroyBean(DefaultSingletonBeanRegistry.java:578)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingleton(DefaultSingletonBeanRegistry.java:554)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.destroySingleton(DefaultListableBeanFactory.java:961)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingletons(DefaultSingletonBeanRegistry.java:523)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.destroySingletons(DefaultListableBeanFactory.java:968)
at org.springframework.context.support.AbstractApplicationContext.destroyBeans(AbstractApplicationContext.java:1033)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:555)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151)
at com.system.MaterialsApplication.main(MaterialsApplication.java:56)
09:57:34.959 [main] ERROR o.s.boot.SpringApplication - Application startup failed
org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.system.MaterialsApplication]; nested exception is java.lang.IllegalStateException: Failed to introspect annotated methods on class org.springframework.boot.web.support.SpringBootServletInitializer$ErrorPageFilterConfiguration
at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:180)
at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:308)
at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:270)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:93)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:686)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151)
at com.system.MaterialsApplication.main(MaterialsApplication.java:56)
Caused by: java.lang.IllegalStateException: Failed to introspect annotated methods on class org.springframework.boot.web.support.SpringBootServletInitializer$ErrorPageFilterConfiguration
at org.springframework.core.type.StandardAnnotationMetadata.getAnnotatedMethods(StandardAnnotationMetadata.java:163)
at org.springframework.context.annotation.ConfigurationClassParser.retrieveBeanMethodMetadata(ConfigurationClassParser.java:360)
at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:294)
at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
at org.springframework.context.annotation.ConfigurationClassParser.processMemberClasses(ConfigurationClassParser.java:329)
at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:247)
at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:197)
at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:166)
... 12 common frames omitted
Caused by: java.lang.NoClassDefFoundError: javax/servlet/Filter
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:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.getDeclaredMethods(Class.java:1975)
at org.springframework.core.type.StandardAnnotationMetadata.getAnnotatedMethods(StandardAnnotationMetadata.java:152)
... 20 common frames omitted
Caused by: java.lang.ClassNotFoundException: javax.servlet.Filter
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 36 common frames omitted
主要看Caused by: java.lang.ClassNotFoundException: javax.servlet.Filter這個，可知錯誤是由這個導致的，解決方法如下：
將spring-boot-starter-tomcat依賴中的<scope>provided</scope>註釋掉
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <!--<scope>provided</scope>--> </dependency>
