【已解决】升级至JDK11，报java.lang.NoClassDefFoundError: javax/xml/bind/ValidationException

Springboot项目从JDK8升级至JDK11，编译通过，启动运行时出现下面的错误：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'objectMapperConfigurer' defined in class path resource [springfox/documentation/spring/web/SpringfoxWebMvcConfiguration.class]:
BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration': BeanPostProcessor before instantiation of bean failed; 
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.cache.config.internalCacheAdvisor' defined in class path resource [org/springframework/cache/annotation/ProxyCachingConfiguration.class]: Bean instantiation via factory method failed; 
nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cache.interceptor.BeanFactoryCacheOperationSourceAdvisor]: Factory method 'cacheAdvisor' threw exception; 
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cacheAutoConfigurationValidator': Unsatisfied dependency expressed through field 'cacheProperties'; 
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'spring.cache-org.springframework.boot.autoconfigure.cache.CacheProperties': Initialization of bean failed; 
nested exception is java.lang.NoClassDefFoundError: javax/xml/bind/ValidationException

意思是初始化objectMapperConfigurer时，出现了NoClassDefFoundError，因为找不到 javax/xml/bind/ValidationException 这个类。

项目中切回JDK8，查找javax/xml/bind/ValidationException 这个类，可以发现，它在 rt.jar 这个包里；

项目中切回JDK11，查找javax/xml/bind/ValidationException 这个类，已经从JDK里找不到了，说明时缺少相关Jar包。

补充：
从java 9中引入了模块的概念，默认情况下，Java SE中将不再包含java EE 的Jar包，因此不再包含在Java SE 9默认的类路径，而在 java 6/7/8 时关于这个API都是捆绑在一起的。
在Java11中，它们完全从JDK中删除。
上图中的jaxb-api 就是Java EE的jar包，所以不存在。

手动引入相关Jar包：

	javax.xml.bind
	jaxb-api
	2.3.1