不会触发针对第三方JAR类的切入点

Question

As a temporary fix of the bug https://github.com/spring-projects/spring-hateoas/issues/220 , I would like modify the return value of org.springframework.hateoas.core.AnnotationMappingDiscoverer.getMapping methods so that I can resolve placeholders manually. Here is the aspect I tried:

<aop:aspectj-autoproxy />

@Component
@Aspect
public class AnnotationMappingDiscovererFix {

  @Around("execution(* org.springframework.hateoas.core.AnnotationMappingDiscoverer.getMapping(..))")
  public Object resolvePlaceholders(ProceedingJoinPoint joinPoint) throws Throwable {
    Object mapping = joinPoint.proceed();
    // resolve placeholders manually...
    return mapping;
  }

}

But this pointcut gets never triggered, any idea why?

Answer 1

With proxy-based Spring AOP you can only target Spring beans/components. I am not a Spring user, so I do not know for sure, but I do not think that you can actually intercept Spring framework classes via its own AOP framework due to "hen vs. egg" bootstrapping problems.

But if you use full AspectJ via load-time weaving (LTW), you should be able to achieve what you want because the AspectJ weaving agent ( aspectjweaver.jar ) is loaded before the Spring classes and thus can modify them during classloading phase. The Spring documentation explains how to use AspectJ in connection with Spring.