Spring在应用程序上下文启动时去创建所有的单例bean对象, 而@Lazy注解可以延迟加载bean对象,即在使用时才去初始化。所以,@Lazy注解, 一是可以减少Spring的IOC容器启动时的加载时间, 二是可以解决bean的循环依赖问题

今天调试项目代码，出现的引resource的Injection报错，查原因查了好长时间才找到，现在这里总结一下，以免以后忘掉以及给大家参考。

最终原因是循环调用，也就是我要注入的那个类也调用了我当前在写的类；

报错大致内容入下：

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-11-08 16:49:54.102 ERROR 3360 --- [           main] o.s.boot.SpringApplication               : Application startup failed
 
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'workFlowBusinessServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'workFlowServiceGenericImpl': Bean with name 'workFlowServiceGenericImpl' has been injected into other beans [workFlowDemandServiceImpl,workFlowServiceImpl,workFlowPlanServiceImpl] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using 'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example.
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:321) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) ~[spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) ~[spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:134) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE]
	at com.ai.rai.group.workflow.WorkflowBootStartApplication.main(WorkflowBootStartApplication.java:45) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'workFlowServiceGenericImpl': Bean with name 'workFlowServiceGenericImpl' has been injected into other beans [workFlowDemandServiceImpl,workFlowServiceImpl,workFlowPlanServiceImpl] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using 'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example.
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:585) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:518) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:496) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:627) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:169) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:318) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	... 15 common frames omitted

循环依赖参考：链接1，链接2