AOP：在一个切入点中支持@annotation 和@within

Question

我有一个注释可以放在 class 或方法上：

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
public @interface TestAspectAnnotation {
    String[] tags() default {};
}

我想要一个单一的建议方法来处理 class 级别和方法级别的用法：

@Around(value = "@annotation(annotation) || @within(annotation)", argNames = "pjp,annotation")
public Object testAdvice(ProceedingJoinPoint pjp,
                         TestAspectAnnotation annotation) throws Throwable {

        String[] tags = annotation.tags();

        Stopwatch stopwatch = Stopwatch.createStarted();
        Object proceed = pjp.proceed();
        stopwatch.stop();
        long executionTime = stopwatch.elapsed(TimeUnit.MILLISECONDS);

        sendMetrics(tags, executionTime);

        return proceed;

    }

当我用 TestAspectAnnotation(tags="foo") 注释 class 时，这工作正常。

但是，如果我注释一个方法，annotation 参数将是 null。

有趣的是，如果我颠倒切入点指示符的顺序 ("@within(annotation) || @annotation(annotation)")，那么我会遇到相反的问题：方法级注释可以正常工作，但 class 级注释会annotation 参数的结果是 null。

有没有办法有一个切入点和建议来支持 class 级别和方法级别的注释？

Answer 1

Is there a way have a single pointcut and advice

我最近遇到了类似的问题，尝试了各种方法，但都无济于事。我最终将 "or" 切入点拆分为两个单独的切入点，并从两条建议中调用相同的方法。

我已经建立了一个小型演示项目来说明我已经建立的工作解决方案。希望对您有所帮助：

@Component
@Aspect
public class SomeAspect {
    @Around(value = "@within(annotation)", argNames = "pjp,annotation")
    public Object methodAdvice(ProceedingJoinPoint pjp, SomeAnnotation annotation) throws Throwable {
        return logTags(pjp, annotation);
    }

    @Around(value = "@annotation(annotation)", argNames = "pjp,annotation")
    public Object classAdvice(ProceedingJoinPoint pjp, SomeAnnotation annotation) throws Throwable {
        return logTags(pjp, annotation);
    }

    private Object logTags(ProceedingJoinPoint pjp, SomeAnnotation annotation) throws Throwable {
        Stream.of(annotation.tags()).forEach(System.out::println);
        return pjp.proceed();
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
public @interface SomeAnnotation {
    String[] tags() default {};
}

@Service
@SomeAnnotation(tags = {"c", "d"})
public class SomeService {
    @SomeAnnotation(tags = {"a", "b"})
    public void test() {
    }
}

@SpringBootApplication
public class Application implements ApplicationRunner {
    @Autowired private SomeService someService;

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Override
    public void run(ApplicationArguments args) throws Exception {
        someService.test();
    }
}

AOP：在一个切入点中支持@annotation 和@within

AOP: Supporting @annotation and @within in one pointcut

spring

spring-boot

aop

spring-aop