Injection with `@Resource`

Infra 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. Infra supports this pattern for Infra-managed objects as well.

@Resource takes a name attribute. By default, Infra 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`.

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;
  }
}

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 Infra SimpleJndiBeanFactory explicitly. However, we recommend that you rely on the default behavior and use Infra 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`.

Injection with @Resource

Injection with `@Resource`