`@target`注解在使用Spring AOP时无法正常工作。

huangapple
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英文:

the @target annotation does not work when i work with spring aop

问题

以下是翻译好的内容：

当我在Spring AOP拦截类上使用注解时，我使用了@target限制匹配方法。但在调试时，出现了以下错误。

org.springframework.context.ApplicationContextException: 无法启动嵌入式容器；嵌入式异常为 org.springframework.boot.context.embedded.EmbeddedServletContainerException: 无法启动嵌入式Tomcat
    ...
    ... （错误堆栈信息）
    ...

我的切入点如下：

@Pointcut("target(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}

其中TimeIt是一个注解：

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
public @interface TimeIt {
    boolean enabled() default true;
}

我将切入点修改为以便运行：

@Pointcut("@within(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}

我不太明白的是，MetricsFilter类没有这个注解，为什么会生成代理？
有人可以帮助我吗？非常感谢。

英文:

When I used the annotation on the spring aop interception class, I used a @target limit matching method. But when debugging, the following error is prompted.

org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:138)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:536)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:123)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:666)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:353)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:300)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1082)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1071)
at com.example.springbootdemo.SpringbootdemoApplication.main(SpringbootdemoApplication.java:20)
Caused by: org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:135)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.<init>(TomcatEmbeddedServletContainer.java:87)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getTomcatEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:535)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:177)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory$$FastClassBySpringCGLIB$$bc74f446.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:736)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:173)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:671)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory$$EnhancerBySpringCGLIB$$bda70dbb.getEmbeddedServletContainer(<generated>)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:162)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:135)
... 8 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'metricsFilter' defined in class path resource [org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfiguration.class]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class org.springframework.boot.actuate.autoconfigure.MetricsFilter: Common causes of this problem include using a final class or a non-visible class; nested exception is java.lang.IllegalArgumentException: Cannot subclass final class org.springframework.boot.actuate.autoconfigure.MetricsFilter
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:481)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.boot.web.servlet.ServletContextInitializerBeans.getOrderedBeansOfType(ServletContextInitializerBeans.java:212)
at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAsRegistrationBean(ServletContextInitializerBeans.java:165)
at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAsRegistrationBean(ServletContextInitializerBeans.java:160)
at org.springframework.boot.web.servlet.ServletContextInitializerBeans.addAdaptableBeans(ServletContextInitializerBeans.java:145)
at org.springframework.boot.web.servlet.ServletContextInitializerBeans.<init>(ServletContextInitializerBeans.java:78)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.getServletContextInitializerBeans(EmbeddedWebApplicationContext.java:240)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.selfInitialize(EmbeddedWebApplicationContext.java:214)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.access$000(EmbeddedWebApplicationContext.java:91)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext$1.onStartup(EmbeddedWebApplicationContext.java:205)
at org.springframework.boot.context.embedded.tomcat.TomcatStarter.onStartup(TomcatStarter.java:53)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5154)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1412)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1402)
at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
at java.util.concurrent.FutureTask.run(FutureTask.java)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class org.springframework.boot.actuate.autoconfigure.MetricsFilter: Common causes of this problem include using a final class or a non-visible class; nested exception is java.lang.IllegalArgumentException: Cannot subclass final class org.springframework.boot.actuate.autoconfigure.MetricsFilter
at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:209)
at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:109)
at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.createProxy(AbstractAutoProxyCreator.java:463)
at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.wrapIfNecessary(AbstractAutoProxyCreator.java:346)
at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessAfterInitialization(AbstractAutoProxyCreator.java:295)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:421)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1634)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
... 24 common frames omitted
Caused by: java.lang.IllegalArgumentException: Cannot subclass final class org.springframework.boot.actuate.autoconfigure.MetricsFilter
at org.springframework.cglib.proxy.Enhancer.generateClass(Enhancer.java:565)
at org.springframework.cglib.transform.TransformingClassGenerator.generateClass(TransformingClassGenerator.java:33)
at org.springframework.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
at org.springframework.aop.framework.CglibAopProxy$ClassLoaderAwareUndeclaredThrowableStrategy.generate(CglibAopProxy.java:1001)
at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:329)
at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:492)
at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:93)
at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:91)
at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
at java.util.concurrent.FutureTask.run(FutureTask.java)
at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:116)
at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291)
at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:480)
at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:337)
at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:54)
at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:201)
... 31 common frames omitted

My cut point is like this

@Pointcut("@target(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}

Where TimeIt is a annotation:

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE,ElementType.METHOD})
public @interface TimeIt {
boolean enabled() default true;
}

I changed the cut point to be able to run

@Pointcut("@within(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}

What I don't quite understand is that the MetricsFilter class doesn't have this annotation, so why generate a proxy?
Can anyone help me? Thank you very much.

答案1

得分: 0

  • 关于在Spring AOP和AspectJ中的@target()和@within()之间的区别，参见我在这里的回答。
  • 你的注解使用了@Target({ElementType.TYPE, ElementType.METHOD})，但是你的切点只针对带注解的类型，而不是带注解的方法。如果要针对方法使用，你需要使用@annotation。也就是说，你带注解的方法永远不会被这个切点匹配，因此通知也不会触发。
  • 你遇到的异常可能来自于另一对切点/通知，而不是你在问题中展示的那对切点/通知。可能是一些全局的切点，比如execution(* *(..))、within(*)或者target(*)，它们会尝试织入所有类型的Spring组件，包括你自己的和内部的组件。所以你需要将另一个切点限制在类似于execution(* my.base.package..*(..))、within(my.base.package..*)或者target(my.base.package..*)这样的范围内，或者至少排除掉你不想通过!within(org.springframework..*)拦截的内部Spring包。
英文:

I cannot run your code because you only provide a few little snippets, but what I noticed is:

  • As for the difference between @target() and @within() in Spring AOP and also in AspectJ, see my answer here.
  • Your annotation has @Target({ElementType.TYPE, ElementType.METHOD}), but both your pointcuts only target annotated types, not annotated methods. For that you would need to use @annotation. I.e. your annotated method will never be matched by this pointcut and consequently the advice will never fire.
  • Your exception must come from another pointcut/advice pair, not the ones you have shown in your question - probably something global like execution(* *(..)) or within(*) or target(*) which will try to weave into all kinds of Spring components, both your own and internal ones. So you need to limit that other pointcut to something like execution(* my.base.package..*(..)) or within(my.base.package..*) or target(my.base.package..*) or at least exclude internal Spring packages you don't wish to intercept via !within(org.springframework..*).

huangapple
  • 本文由 发表于 2020年4月10日 17:06:36
  • 转载请务必保留本文链接：https://go.coder-hub.com/61137118.html
  • aop
  • java
  • spring
  • spring-boot
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