面向方面的编程Java-获取注释参数

Question

So I have defined 3 classes, as given below. What I am trying to do, is give input to an annotation, and then when an annotated function throws an exception, to use those parameters to do some stuff.

So basically, in the CreateFluxoTicket class in the aferThrowing function, I want to gain access to the "shortDescription" and "details" attributes.

I went through numerous links and answers, but I fail to get the parameters. One thing which I tried to do is shown below, but the parameter list is empty (The output is - "Parameter Types size = 0")

public class TemporaryClass {
    @Fluxo(shortDescription = "shortDescription", details = "details")
    public void tempFluxo() {
        System.out.println(50 / 0);
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Fluxo {
    String shortDescription();
    String details();
}

@Aspect
public class CreateFluxoTicket {
    @AfterThrowing(pointcut = "@annotation(metrics.annotations.Fluxo)", throwing = "e")
    public void afterThrowingException(JoinPoint jointPoint, Throwable e) {
        Signature signature = jointPoint.getStaticPart().getSignature();
        if (signature instanceof MethodSignature) {
            MethodSignature ms = (MethodSignature) signature;
            Class<?>[] parameterTypes = ms.getParameterTypes();
            System.out.println("Parameter Types size = " + parameterTypes.length);
            for (final Class<?> pt : parameterTypes) {
                System.out.println("Parameter type:" + pt);
            }
        }
    }
}

Answer 1

You can bind the annotation to a parameter similar to the exception. Try this:

package metrics.aspect;

import metrics.annotations.Fluxo;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;

@Aspect
public class CreateFluxoTicket {
    @AfterThrowing(
        pointcut = "execution(* *(..)) && @annotation(fluxo)",
        throwing = "throwable"
    )
    public void afterThrowingException(
        JoinPoint thisJoinPoint,
        Fluxo fluxo,
        Throwable throwable
    ) {
        System.out.println(thisJoinPoint + " -> " + fluxo.shortDescription());
    }
}

As you can see, I also limited the pointcut to method execution s because otherwise call s would also trigger the advice and you would see the output twice.