接口 ResourceLoaderAware

public interface ResourceLoaderAware
extends Aware

Interface to be implemented by any object that wishes to be notified of the ResourceLoader (typically the ApplicationContext) that it runs in. This is an alternative to a full ApplicationContext dependency via the ApplicationContextAware interface.

Note that Resource dependencies can also be exposed as bean properties of type Resource, populated via Strings with automatic type conversion by the bean factory. This removes the need for implementing any callback interface just for the purpose of accessing a specific file resource.

You typically need a ResourceLoader when your application object has to access a variety of file resources whose names are calculated. A good strategy is to make the object use a DefaultResourceLoader but still implement ResourceLoaderAware to allow for overriding when running in an ApplicationContext. See ReloadableResourceBundleMessageSource for an example.

A passed-in ResourceLoader can also be checked for the ResourcePatternResolver interface and cast accordingly, in order to resolve resource patterns into arrays of Resource objects. This will always work when running in an ApplicationContext (since the context interface extends the ResourcePatternResolver interface). Use a PathMatchingResourcePatternResolver as default; see also the ResourcePatternUtils.getResourcePatternResolver method.

As an alternative to a ResourcePatternResolver dependency, consider exposing bean properties of type Resource array, populated via pattern Strings with automatic type conversion by the bean factory at binding time.