Mongodb 的自动配置类MongoDataAutoConfiguration 是如何加载的

发现一个工具插件很不错 AmaterasUML 可以根据堆栈信息导出时序图

错误信息

2018-11-29 10:45:51,028 ERROR main o.s.b.SpringApplication:771 - Application startup failed
java.lang.IllegalStateException: Error processing condition on org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration.mongoMappingContext
	at org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration.mongoMappingContext(MongoDataAutoConfiguration.java:118)
	at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:64)
	at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:102)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:178)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:140)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:116)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:320)
	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:687)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:525)
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
	at com.snail.sncp.mobile.account.MobileAccountApplication.main(MobileAccountApplication.java:15)
Caused by: java.lang.IllegalStateException: @ConditionalOnMissingBean did not specify a bean using type, name or annotation and the attempt to deduce the bean's type failed
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.validate(OnBeanCondition.java:309)
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.(OnBeanCondition.java:299)
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchOutcome(OnBeanCondition.java:108)
	at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:47)
	... 17 common frames omitted
Caused by: org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanTypeDeductionException: Failed to deduce bean type for org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration.mongoMappingContext
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.addDeducedBeanTypeForBeanMethod(OnBeanCondition.java:362)
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.addDeducedBeanType(OnBeanCondition.java:346)
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.(OnBeanCondition.java:293)
	... 19 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/springframework/data/mapping/context/AbstractMappingContext
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(Unknown Source)
	at java.security.SecureClassLoader.defineClass(Unknown Source)
	at java.net.URLClassLoader.defineClass(Unknown Source)
	at java.net.URLClassLoader.access$100(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at org.springframework.util.ClassUtils.forName(ClassUtils.java:250)
	at org.springframework.boot.autoconfigure.condition.OnBeanCondition$BeanSearchSpec.addDeducedBeanTypeForBeanMethod(OnBeanCondition.java:356)
	... 21 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.springframework.data.mapping.context.AbstractMappingContext
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 35 common frames omitted
Exception in thread "main" 2018-11-29 10:45:51,031  INFO main o.s.b.c.e.AnnotationConfigEmbeddedWebApplicationContext:984 - Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@3762c4fc: startup date [Thu Nov 29 10:45:50 CST 2018]; parent: org.springframework.context.annotation.AnnotationConfigApplicationContext@72cc7e6f

很明显 ，MongoDataAutoConfiguration的自动配置类报错了
根据这个我们能够得到时序图

MongoDataAutoConfiguration加载

结论

springboot(cloud)里面加载MongoDataAutoConfiguration的主要路径
AbstractApplicationContext：完成Bean工厂的创建
ConfigurationClassBeanDefinitionReader：根据配置加载指定的配置Bean
MongoDataAutoConfiguration：自动化配置