[java][annotation][@Aspect]Java注解与切面使用

本是古典何须时尚 2022-01-13 14:19 257阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

import org.springframework.kafka.annotation.KafkaListener;
    
    import java.lang.annotation.*;
    
    
    @Target({ ElementType.TYPE, ElementType.METHOD, ElementType.ANNOTATION_TYPE })
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @KafkaListener
    public @interface Listener {
    
        String[] topics() default {};
    
    }
    
    import lombok.extern.slf4j.Slf4j;
    import org.apache.kafka.clients.consumer.ConsumerRecord;
    import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.reflect.MethodSignature;
    import org.springframework.stereotype.Component;
    
    import java.lang.reflect.Method;
    
    @Aspect
    @Component
    @Slf4j
    public class ListenAspect {
        @Before("@annotation(Listener)")
        public void beforeListener(JoinPoint point) {
            Object[] args = point.getArgs();
            if (args[0] != null && args[0] instanceof ConsumerRecord) {
                ConsumerRecord consumerRecord = (ConsumerRecord) args[0];
                log.debug("consumerRecord:{}", consumerRecord.toString());
    
                String value = consumerRecord.value().toString();
                log.trace("value:{}", value);
            }
    
            Class<?> className = point.getTarget().getClass();
            String methodName = point.getSignature().getName();
            Class[] argClass = ((MethodSignature) point.getSignature()).getParameterTypes();
            log.trace("className:" + className);
            log.trace("methodName:" + methodName);
            log.trace("argClass:" + argClass);
    
            if (argClass[0] != null) {
                log.trace("argClass[0]:" + argClass[0].toString());
    //            try {
    //                ConsumerRecord consumerRecord = (ConsumerRecord)argClass[0].newInstance();
    //                log.debug("consumerRecord:{}", consumerRecord.toString());
    //            } catch (InstantiationException|IllegalAccessException e) {
    //                e.printStackTrace();
    //            }
            }
    
            try {
                Method method = className.getMethod(methodName, argClass);
                log.trace("method:" + method);
    
                if (method.isAnnotationPresent(Listener.class)) {
                    Listener annotation = method.getAnnotation(Listener.class);
                    log.trace("annotation:" + annotation);
                    log.trace("topics:" + annotation.topics());
                }
            } catch (Exception e) {
                log.warn(e.getMessage(), e);
            }
        }
    }

转载于:https://my.oschina.net/u/2464371/blog/3056316

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220113/ee6ca0d029a3451a838c6844f24df78f.png