Spring-AOP：@在异常：java.lang.IlLegalArgumentException：引用的错误类型不是批注类型 [英] Spring - AOP: @within Exception: java.lang.IllegalArgumentException: error Type referred to is not an annotation type

问题描述

我是AOP和AspectJ的新手。我正尝试围绕元素类型为TYPE的自定义注释编写一个自定义逻辑。我还想在我的注释下使用这些参数来在环绕方法中编写一个定制逻辑。我收到了下面提到的错误。我试着阅读了多个来源，大多数来源都与使用@annotation有关。我发现很难理解这一点。谁能解释一下，为什么以下@within的方法不适用于一些明显的例子？

Annotation(Slf4jTrace.java)：

package io.ud.project.falcon.logging;

import io.ud.project.falcon.logging.generator.AbstractLogTraceIdGenerator;
import io.ud.project.falcon.logging.generator.DefaultLogTraceIdGenerator;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Slf4jTrace {

    String traceKey() default "traceId";

    Class<? extends AbstractLogTraceIdGenerator> traceValueGenerator() default DefaultLogTraceIdGenerator.class;

}

方面Component(Slf4jTraceAspect.java)：

package io.ud.project.falcon.logging;

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

@Aspect
@Component
@SuppressWarnings("unused")
@Slf4j
public class Slf4jTraceAspect {

    @Pointcut("execution(public * *(..))")
    public void publicOperation() {
        //Using this pointcut annotation for Around method.
    }

    @Around(value = "@within(slf4jTrace) && publicOperation()")
    public void logTrace(ProceedingJoinPoint joinPoint, Slf4jTrace slf4jTrace) throws Throwable {
        //Custom logic that uses slf4jTrace's parameters        
        joinPoint.proceed();
        //Custom logic that uses slf4jTrace's parameters
    }
}

带注释的类(Foo.java)：

package io.ud.project.falcon.logging;

import io.ud.project.falcon.logging.Slf4jTrace;

@Slf4jTrace(traceKey = "auditID")
public class Foo {

    public void doSomething() {
        //Something happens here.
    }

}

应用程序启动时出错：

, 2021-01-02 22:16:41,340, ERROR [main] o.s.b.SpringApplication.reportFailure(833) | Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'objectMapperConfigurer' defined in springfox.documentation.spring.web.SpringfoxWebMvcConfiguration
: BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration': BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.cache.annotation.ProxyCachingConfiguration': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: error Type referred to is not an annotation type: slf4jTrace
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:497)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:312)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:205)
        at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:238)
        at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:709)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:534)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:327)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234)
        at io.ud.project.falcon.FalconApplication.main(FalconServiceApplication.java:65)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

推荐答案

我没有尝试运行您的代码，但当我浏览它时，立即注意到了两件事：

• BeanCreationException如果方面切入点太过宽泛，就经常会出现内部Spring类型的问题，也就是说，方面也被编织到了Spring类中(即使没有在其中执行)。在这种情况下，您希望通过向切入点添加类似... && within(my.package..*)的内容来限制方面范围。或者，如果您的方面位于可能针对未知包名运行的库中，您可以通过!within(org.springframework..*)或任何适用于您的包名来排除引起问题的Spring包或类。另请参阅my answer here。

• 您的@Around建议返回void，即它还将只匹配void方法，这可能不是您想要的。为了匹配非空方法，建议必须返回void以外的内容，如果要匹配任何返回类型，通常只返回Object。还要确保返回proceed()的结果或您希望返回的任何其他结果。

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