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Spring依赖中一个接口多个实现问题解决及其分析

更新时间：2022-03-23 13:55:21阅读数：826 发布者：落幕

在spring中一个接口有多个实现时，启动时就会出现异常：

  1. 2022-03-23 13:47:38.606 [DEBUG] [at org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter.report(LoggingFailureAnalysisReporter.java:37)] Application failed to start due to an exception
  2. org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.speechb.service.TestService' available: expected single matching bean but found 2: test1,test2
  3.     at org.springframework.beans.factory.config.DependencyDescriptor.resolveNotUnique(DependencyDescriptor.java:220)
  4.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1285)
  5.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227)
  6.     at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
  7.     at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)
  8.     at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
  9.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1420)
  10.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
  11.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516)
  12.     at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324)
  13.     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)

继续往下翻，会发现spring也提供了解决方法

  1. Action:
  3. Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

可以从中看出可以使用@ Primary提供一个默认实现，或者使用@ Qualifier指定特定实现