Spring Couldn't autowired,there is more than one bean of `` type

Question

Here is my question:I have a base interface and two implementation class.

And a Service class has a dependencies on the base interface, the code is like this:

@Component public interface BaseInterface {} 

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@Component public class ClazzImplA implements  BaseInterface{} 

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@Component public class ClazzImplB implements  BaseInterface{} 

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And the configuration is like this :

@Configuration public class SpringConfig {     @Bean     public BaseInterface clazzImplA(){         return new ClazzImplA();     }      @Bean     public BaseInterface clazzImplB(){         return new ClazzImplB();     } } 

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The service class has dependencies on the base interface will decide to autowire which Implementation by some business logic.And the code is like this:

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@Service @SpringApplicationConfiguration(SpringConfig.class) public class AutowiredClazz {     @Autowired     private BaseInterface baseInterface;      private AutowiredClazz(BaseInterface baseInterface){         this.baseInterface = baseInterface;     } } 

And the IDEA throws a exception:Could not autowire.There is more than one bean of BaseInterface type.

Although it can be solved by using @Qualifier,but in this situation I can't choose the dependencies class.

@Autowired @Qualifier("clazzImplA") private BaseInterface baseInterface; 

I tried to read the spring document and it provide a Constructor-based dependency injection but I'm still confused by the problem.

can anyone help me ?

Answer 1

Spring is confused between the 2 beans you have declared in you configuration class so you can use @Qualifier annotation along with @Autowired to remove the confusion by specifying which exact bean will be wired, apply these modifications on your configuration class

@Configuration public class SpringConfig {     @Bean(name="clazzImplA")     public BaseInterface clazzImplA(){         return new ClazzImplA();     }      @Bean(name="clazzImplB")     public BaseInterface clazzImplB(){         return new ClazzImplB();     } } 

then at @autowired annotation

@Service @SpringApplicationConfiguration(SpringConfig.class) public class AutowiredClazz {     @Autowired     @Qualifier("the name of the desired bean")     private BaseInterface baseInterface;      private AutowiredClazz(BaseInterface baseInterface){         this.baseInterface = baseInterface;     } }