org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.example.SpringBootJdbcDemoApplication.SpringBootJdbcDemoApplication': Unsatisfied dependency expressed through field 'userRepository': No qualifying bean of type [com.example.repositories.UserRepository] found for dependency [com.example.repositories.UserRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.example.repositories.UserRepository] found for dependency [com.example.repositories.UserRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:569)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
无法注入Dao中的Bean！
解决分析后来经研究发现，SpringBoot项目的Bean装配默认规则是根据Application类所在的包位置从上往下扫描！ “Application类”是指SpringBoot项目入口类。这个类的位置很关键：
如果Application类所在的包为：io.github.gefangshuai.app
，则只会扫描io.github.gefangshuai.app
包及其所有子包，如果service或dao所在包不在io.github.gefangshuai.app
及其子包下，则不会被扫描！
知道这一点非常关键，不知道Spring文档里有没有给出说明，如果不知道还真是无从解决。
转：http://blog.csdn.net/gefangshuai/article/details/50328451,http://412887952-qq-com.iteye.com/blog/2292733
在开发中我们知道Spring Boot默认会扫描启动类同包以及子包下的注解，那么如何进行改变这种扫描包的方式呢，原理很简单就是：@ComponentScan注解进行指定要扫描的包以及要扫描的类。
