本文介绍了当我使用Spring AOP时，@target注释不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
当我在spring aop拦截类上使用注释时，我使用了@target限制匹配方法.但是在调试时，会提示以下错误.
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
我的切入点是这样的
@Pointcut("@target(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}
时间是注释的地方
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE,ElementType.METHOD})
public @interface TimeIt {
boolean enabled() default true;
}
我更改了切割点以便能够运行
I changed the cut point to be able to run
@Pointcut("@within(com.example.springbootdemo.aspect.TimeIt)")
public void calcTime() {}
我不太了解MetricsFilter类没有此注释，那么为什么要生成代理?谁能帮我?非常感谢.
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.
推荐答案
我无法运行您的代码，因为您仅提供了一些小片段，但我注意到的是:
I cannot run your code because you only provide a few little snippets, but what I noticed is:
- 关于Spring AOP和AspectJ中
@target()和@within()之间的区别，请参见. - 您的注释具有
@Target({ElementType.TYPE，ElementType.METHOD})，但是您的两个切入点都仅针对带注释的类型，而不是带注释的方法.为此，您需要使用@annotation.IE.您注释的方法将永远不会与此切入点匹配，因此建议也永远不会触发. - 您的异常必须来自另一个切入点/建议对，而不是您在问题中显示的对-可能是全局性的，例如
execution(* *(..))或within(*)或target(*)，它们将尝试并入各种Spring组件，包括您自己的和内部的.因此，您需要将其他切入点限制为execution(* my.base.package .. *(..))或within(my.base.package .. *)或target(my.base.package .. *)或至少排除您不希望通过！within(org.springframework .. *)截取的内部Spring软件包..
- 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(* *(..))orwithin(*)ortarget(*)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 likeexecution(* my.base.package..*(..))orwithin(my.base.package..*)ortarget(my.base.package..*)or at least exclude internal Spring packages you don't wish to intercept via!within(org.springframework..*).
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