Package org.springframework.context.annotation

Annotation Interface ComponentScan

@Retention(RUNTIME) @Target(TYPE) @Documented @Repeatable(ComponentScans.class) public @interface ComponentScan
Configures component scanning directives for use with @Configuration classes.

Provides support comparable to Spring's <context:component-scan> XML namespace element.

Either basePackageClasses() or basePackages() (or its alias value()) may be specified to define specific packages to scan. If specific packages are not defined, scanning will occur recursively beginning with the package of the class that declares this annotation.

Note that the <context:component-scan> element has an annotation-config attribute; however, this annotation does not. This is because in almost all cases when using @ComponentScan, default annotation config processing (e.g. processing @Autowired and friends) is assumed. Furthermore, when using AnnotationConfigApplicationContext, annotation config processors are always registered, meaning that any attempt to disable them at the @ComponentScan level would be ignored.

See @Configuration's Javadoc for usage examples.

@ComponentScan can be used as a repeatable annotation. @ComponentScan may also be used as a meta-annotation to create custom composed annotations with attribute overrides.

Locally declared @ComponentScan annotations always take precedence over and effectively hide @ComponentScan meta-annotations, which allows explicit local configuration to override configuration that is meta-present (including composed annotations meta-annotated with @ComponentScan).

Since:
3.1
Author:
Chris Beams, Juergen Hoeller, Sam Brannen
See Also:

  • Element Details

    • value

      @AliasFor("basePackages") String[] value
      Alias for basePackages().

      Allows for more concise annotation declarations if no other attributes are needed — for example, @ComponentScan("org.my.pkg") instead of @ComponentScan(basePackages = "org.my.pkg").

      Default:
      {}

    • basePackages

      @AliasFor("value") String[] basePackages
      Base packages to scan for annotated components.

      value() is an alias for (and mutually exclusive with) this attribute.

      Use basePackageClasses() for a type-safe alternative to String-based package names.

      Default:
      {}

    • basePackageClasses

      Class<?>[] basePackageClasses
      Type-safe alternative to basePackages() for specifying the packages to scan for annotated components. The package of each class specified will be scanned.

      Consider creating a special no-op marker class or interface in each package that serves no purpose other than being referenced by this attribute.

      Default:
      {}

    • nameGenerator

      Class<? extends BeanNameGenerator> nameGenerator
      The BeanNameGenerator class to be used for naming detected components within the Spring container.

      The default value of the BeanNameGenerator interface itself indicates that the scanner used to process this @ComponentScan annotation should use its inherited bean name generator, e.g. the default AnnotationBeanNameGenerator or any custom instance supplied to the application context at bootstrap time.

      See Also:
      Default:
      org.springframework.beans.factory.support.BeanNameGenerator.class

    • scopeResolver

      Class<? extends ScopeMetadataResolver> scopeResolver
      The ScopeMetadataResolver to be used for resolving the scope of detected components.
      Default:
      org.springframework.context.annotation.AnnotationScopeMetadataResolver.class

    • scopedProxy

      ScopedProxyMode scopedProxy
      Indicates whether proxies should be generated for detected components, which may be necessary when using scopes in a proxy-style fashion.

      The default is defer to the default behavior of the component scanner used to execute the actual scan.

      Note that setting this attribute overrides any value set for scopeResolver().

      See Also:
      Default:
      DEFAULT

    • resourcePattern

      String resourcePattern
      Controls the class files eligible for component detection.

      Consider use of includeFilters() and excludeFilters() for a more flexible approach.

      Default:
      "**/*.class"

    • useDefaultFilters

      boolean useDefaultFilters
      Indicates whether automatic detection of classes annotated with @Component @Repository, @Service, or @Controller should be enabled.
      Default:
      true

    • includeFilters

      ComponentScan.Filter[] includeFilters
      Specifies which types are eligible for component scanning.

      Further narrows the set of candidate components from everything in basePackages() to everything in the base packages that matches the given filter or filters.

      Note that these filters will be applied in addition to the default filters, if specified. Any type under the specified base packages which matches a given filter will be included, even if it does not match the default filters (i.e. is not annotated with @Component).

      See Also:
      Default:
      {}

    • excludeFilters

      ComponentScan.Filter[] excludeFilters
      Specifies which types are not eligible for component scanning.
      See Also:
      Default:
      {}

    • lazyInit

      boolean lazyInit
      Specify whether scanned beans should be registered for lazy initialization.

      Default is false; switch this to true when desired.

      Since:
      4.1
      Default:
      false