Cannot create inner bean 'mappingJackson2HttpMessageConverter' of type [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter]

严重: StandardWrapper.Throwable
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter': Cannot create inner bean 'mappingJackson2HttpMessageConverter' of type [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] while setting bean property 'messageConverters' with key [0]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mappingJackson2HttpMessageConverter': Failed to introspect bean class [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] for lookup method metadata: could not find class that it depends on; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:313)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:122)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:382)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:157)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1492)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1237)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:552)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
	at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:668)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:634)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:682)
	at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:553)
	at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:494)
	at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
	at javax.servlet.GenericServlet.init(GenericServlet.java:158)
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1144)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1091)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:983)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4978)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5290)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3839)
	at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:291)
	at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5612)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1389)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1393)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1393)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1361)
	at java.lang.Thread.run(Thread.java:748)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mappingJackson2HttpMessageConverter': Failed to introspect bean class [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] for lookup method metadata: could not find class that it depends on; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:269)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineConstructorsFromBeanPostProcessors(AbstractAutowireCapableBeanFactory.java:1079)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1052)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:299)
	... 35 more

解决办法：
错误是因为 spring4开始，使用了 MappingJackson2HttpMessageConverter替换之前的MappingJacksonHttpMessageConverter，
同时，依赖的jar包也换了。从jackson-mapper-asl，jackson-core-asl,换为了 jackson-core，jackson-databind 

在pom.xml添加相应的包：

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-core</artifactId>
			<version>2.9.8</version>
		</dependency>

		<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-databind</artifactId>
			<version>2.9.8</version>
		</dependency>