基于 Spring 注释和限定符的扫描

Question

有没有办法在春季执行基于注释的组件扫描时应用限定符？

我有几个使用自定义注释 MyAnnotation 注释的类。

@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，扫描带有此注释的类的子集，根据某些条件有选择地说明用户的某些输入。

是否可以说指定一个限定符以及注释，也可以使用组件扫描过滤器指定它，像这样 -

@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 {
}

所以只有ClassOne 被扫描？

Answer 1

您可以实现自定义TypeFilter，以便您的@ComponentScan 看起来像：

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

TypeFilter 实现：

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;
    }

}