org.springframework.beans.factory.NoSuchBeanDefinitionException:

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.zk.test.service.UserServiceImpl] found for dependency: 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.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:993)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:863)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:775)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:489)

... 28 more

经过上网查资料发现出现这类错误的几个主要因素：

       1.扫描包中没有扫描到所需要的类（或者没有扫描包）,spring配置文件有问题也是有可能的,修改配置文件

       2.serviceImpl类中出现死循环,暫時沒遇到

       3.没有在对应的类上加注解,如dao层 @Repository  如service层  @Service

       4.在一二控制器中注入的次数超过了两次，系统不能识别你到底要使用哪一个注入设计；

       5.service和serviceImpl没有放在同一个包下，导致spring扫描的时候没有扫描Impl包