记Springboot项目中@Service(或@Component)注解失效的问题解决方法

一、问题描述

今天基于SpringBoot写好的一个项目程序，启动时，报如下错误：

2020-04-07 14:04:41.420 WARN o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'kafkaConsumerController': Unsatisfied dependency expressed through field 'taskStarter'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'taskStarter': Unsatisfied dependency expressed through field 'taskExecutor'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.weishao.dbpush.service.TaskExecutor' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
2020-04-07 14:04:41.437 INFO org.apache.catalina.core.StandardService - Stopping service [Tomcat]
2020-04-07 14:04:41.475 INFO o.s.b.a.l.ConditionEvaluationReportLoggingListener -

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-04-07 14:04:41.789 ERROR o.s.b.diagnostics.LoggingFailureAnalysisReporter -

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APPLICATION FAILED TO START
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Description:

Field taskExecutor in com.weishao.dbpush.service.TaskStarter required a bean of type 'com.weishao.dbpush.service.TaskExecutor' that could not be found.

The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)

Action:

Consider defining a bean of type 'com.weishao.dbpush.service.TaskExecutor' in your configuration.

而查看com.weishao.dbpush.service.TaskExecutor类的定义，也使用了@Service注解向IOC容器里注入了bean，如下：