Spring註釋和基於限定符的掃描

Question

在執行基於註釋的組件掃描時，是否有一種方法可以在春季應用限定符？

我有幾個類用我的自定義註釋MyAnnotation註釋。

@MyAnnotation 
public class ClassOne { 
} 

@MyAnnotation 
public class ClassTwo { 
} 

@Configuration 
@ComponentScan(basePackages = { "common" }, useDefaultFilters = false, includeFilters = { @ComponentScan.Filter(type = FilterType.ANNOTATION, value = MyAnnotation.class) }) 
public class ClassProvider { 
} 

我想要做的是，掃描類的子集與此註釋，選擇基於一些條件說一些來自用戶的輸入。

是否可以說與註釋一起指定一個限定詞，也與組件掃描過濾器指定它，像這樣 -

@MyAnnotation (qualifier = "one") 
public class ClassOne { 
} 

@MyAnnotation (qualifier = "two") 
public class ClassTwo { 
} 

@Configuration 
@ComponentScan(basePackages = { "common" }, useDefaultFilters = false, includeFilters = { @ComponentScan.Filter(type = FilterType.ANNOTATION, value = MyAnnotation.class, qualifier = "one") }) 
public class ClassProvider { 
} 

因此只有ClassOne被掃描？

Answer 1

您可以實現自定義TypeFilter讓您@ComponentScan可以看起來像：

@ComponentScan(includeFilters = { @ComponentScan.Filter(type = FilterType.CUSTOM, value = MyAnnotation.class) }) 

而且TypeFilter實現：

public class TypeOneFilter implements TypeFilter { 

    @Override 
    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException { 
     final AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata(); 

     if (annotationMetadata.hasAnnotation(MyAnnotation.class.getName())) { 
      final Map<String, Object> attributes = annotationMetadata.getAnnotationAttributes(MyAnnotation.class.getName()); 

      return "one".equals(attributes.get("qualifier")); 
     } 

     return false; 
    } 

}