resource.adoc

Injection with @Resource

Spring also supports injection by using the JSR-250 @Resource annotation (jakarta.annotation.Resource) on fields or bean property setter methods. This is a common pattern in Jakarta EE: for example, in JSF-managed beans and JAX-WS endpoints. Spring supports this pattern for Spring-managed objects as well.

@Resource takes a name attribute. By default, Spring interprets that value as the bean name to be injected. In other words, it follows by-name semantics, as demonstrated in the following example:

Java

public class SimpleMovieLister {

	private MovieFinder movieFinder;

	@Resource(name="myMovieFinder") // (1)
	public void setMovieFinder(MovieFinder movieFinder) {
		this.movieFinder = movieFinder;
	}
}

1. This line injects a @Resource.

Kotlin

class SimpleMovieLister {

	@Resource(name="myMovieFinder") // (1)
	private lateinit var movieFinder:MovieFinder
}

1. This line injects a @Resource.

If no name is explicitly specified, the default name is derived from the field name or setter method. In case of a field, it takes the field name. In case of a setter method, it takes the bean property name. The following example is going to have the bean named movieFinder injected into its setter method:

Java

public class SimpleMovieLister {

	private MovieFinder movieFinder;

	@Resource
	public void setMovieFinder(MovieFinder movieFinder) {
		this.movieFinder = movieFinder;
	}
}

Kotlin

class SimpleMovieLister {

	@set:Resource
	private lateinit var movieFinder: MovieFinder

}

Note

The name provided with the annotation is resolved as a bean name by the ApplicationContext of which the CommonAnnotationBeanPostProcessor is aware. The names can be resolved through JNDI if you configure Spring’s {api-spring-framework}/jndi/support/SimpleJndiBeanFactory.html[SimpleJndiBeanFactory] explicitly. However, we recommend that you rely on the default behavior and use Spring’s JNDI lookup capabilities to preserve the level of indirection.

In the exclusive case of @Resource usage with no explicit name specified, and similar to @Autowired, @Resource finds a primary type match instead of a specific named bean and resolves well known resolvable dependencies: the BeanFactory, ApplicationContext, ResourceLoader, ApplicationEventPublisher, and MessageSource interfaces.

Thus, in the following example, the customerPreferenceDao field first looks for a bean named "customerPreferenceDao" and then falls back to a primary type match for the type CustomerPreferenceDao:

Java

public class MovieRecommender {

	@Resource
	private CustomerPreferenceDao customerPreferenceDao;

	@Resource
	private ApplicationContext context; // (1)

	public MovieRecommender() {
	}

	// ...
}

1. The context field is injected based on the known resolvable dependency type: ApplicationContext.

Kotlin

class MovieRecommender {

	@Resource
	private lateinit var customerPreferenceDao: CustomerPreferenceDao


	@Resource
	private lateinit var context: ApplicationContext // (1)

	// ...
}

1. The context field is injected based on the known resolvable dependency type: ApplicationContext.