老师笔记写不下，就写这里了

先上报错信息，首先声明由于刚开始不想更改版本号，所以我的springboot版本为2.1.1，springcloud版本为Greenwich.M3

2018-12-12 10:30:20.999  INFO 12128 --- [           main] c.c.c.ConfigServicePropertySourceLocator : Fetching config from server at : http://localhost:8080/
2018-12-12 10:30:23.108  INFO 12128 --- [           main] c.c.c.ConfigServicePropertySourceLocator : Located environment: name=order, profiles=[dev], label=null, version=8f6f502827ddbf876e550cc8cea7cc552c7fbaaf, state=null
2018-12-12 10:30:23.108  INFO 12128 --- [           main] b.c.PropertySourceBootstrapConfiguration : Located property source: CompositePropertySource {name='configService', propertySources=[MapPropertySource {name='configClient'}, MapPropertySource {name='https://gitee.com/codelhf/spring-cloud-config/order-dev.yml'}]}
2018-12-12 10:30:23.108  INFO 12128 --- [           main] com.imooc.order.OrderApplication         : No active profile set, falling back to default profiles: default
2018-12-12 10:30:23.499  INFO 12128 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode.
2018-12-12 10:30:23.546  INFO 12128 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 47ms. Found 2 repository interfaces.
2018-12-12 10:30:23.702  INFO 12128 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=258d3afa-936f-387d-970a-20cf7dd7a764
2018-12-12 10:30:23.718  WARN 12128 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'methodValidationPostProcessor' defined in class path resource [org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.class]: Unsatisfied dependency expressed through method 'methodValidationPostProcessor' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.imooc.product.client.ProductClient': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [org.springframework.cloud.openfeign.FeignClientFactoryBean] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
2018-12-12 10:30:23.718  INFO 12128 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-12-12 10:30:23.733 ERROR 12128 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'methodValidationPostProcessor' defined in class path resource [org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.class]: Unsatisfied dependency expressed through method 'methodValidationPostProcessor' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.imooc.product.client.ProductClient': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [org.springframework.cloud.openfeign.FeignClientFactoryBean] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:769) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1288) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1127) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:228) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:707) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
	at com.imooc.order.OrderApplication.main(OrderApplication.java:14) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.imooc.product.client.ProductClient': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [org.springframework.cloud.openfeign.FeignClientFactoryBean] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:265) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineConstructorsFromBeanPostProcessors(AbstractAutowireCapableBeanFactory.java:1236) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1151) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getSingletonFactoryBeanForTypeCheck(AbstractAutowireCapableBeanFactory.java:974) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:848) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:574) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:514) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:477) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:227) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1401) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1200) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1164) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	... 19 common frames omitted
Caused by: java.lang.IllegalStateException: Failed to introspect Class [org.springframework.cloud.openfeign.FeignClientFactoryBean] from ClassLoader [sun.misc.Launcher$AppClassLoader@18b4aac2]
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:686) ~[spring-core-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:583) ~[spring-core-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:568) ~[spring-core-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:248) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	... 32 common frames omitted
Caused by: java.lang.NoClassDefFoundError: feign/Feign$Builder
	at java.lang.Class.getDeclaredMethods0(Native Method) ~[na:1.8.0_172]
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[na:1.8.0_172]
	at java.lang.Class.getDeclaredMethods(Class.java:1975) ~[na:1.8.0_172]
	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:668) ~[spring-core-5.1.3.RELEASE.jar:5.1.3.RELEASE]
	... 35 common frames omitted
Caused by: java.lang.ClassNotFoundException: feign.Feign$Builder
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_172]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_172]
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[na:1.8.0_172]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_172]
	... 39 common frames omitted


Process finished with exit code 1

解决过程在手记中引入product-client依赖报ClassNotFoundException：feign.Feign$Builder