Declaring an Aspect

With @AspectJ support enabled, any bean defined in your application context with a class that is an @AspectJ aspect (has the @Aspect annotation) is automatically detected by Spring and used to configure Spring AOP. The next two examples show the minimal steps required for a not-very-useful aspect.

The first of the two examples shows a regular bean definition in the application context that points to a bean class that is annotated with @Aspect:

  • Java

  • Kotlin

  • Xml

public class ApplicationConfiguration {

	@Bean
	public NotVeryUsefulAspect myAspect() {
		NotVeryUsefulAspect myAspect = new NotVeryUsefulAspect();
		// Configure properties of the aspect here
		return myAspect;
	}
}
class ApplicationConfiguration {

	@Bean
	fun myAspect() = NotVeryUsefulAspect().apply {
		// Configure properties of the aspect here
	}
}
<bean id="myAspect" class="org.springframework.docs.core.aop.ataspectj.aopataspectj.NotVeryUsefulAspect">
	<!-- configure properties of the aspect here -->
</bean>

The second of the two examples shows the NotVeryUsefulAspect class definition, which is annotated with @Aspect:

  • Java

  • Kotlin

@Aspect
public class NotVeryUsefulAspect {
}
@Aspect
class NotVeryUsefulAspect

Aspects (classes annotated with @Aspect) can have methods and fields, the same as any other class. They can also contain pointcut, advice, and introduction (inter-type) declarations.

Autodetecting aspects through component scanning
You can register aspect classes as regular beans in your Spring XML configuration, via @Bean methods in @Configuration classes, or have Spring autodetect them through classpath scanning — the same as any other Spring-managed bean. However, note that the @Aspect annotation is not sufficient for autodetection in the classpath. For that purpose, you need to add a separate @Component annotation (or, alternatively, a custom stereotype annotation that qualifies, as per the rules of Spring’s component scanner).
Advising aspects with other aspects?
In Spring AOP, aspects themselves cannot be the targets of advice from other aspects. The @Aspect annotation on a class marks it as an aspect and, hence, excludes it from auto-proxying.