Question

我有以下奇怪的行为。

当我使用命名切入点时，建议的方法在@AfterThrowing带注释的方法的主体之前运行。但是，如果我使用内联切入点，@AfterThrowing带注释的切入点会先运行。

为什么会这样？

以下是代码：

@Component
@Aspect
public class CustomAspect {

    @AfterThrowing(pointcut = "execution(* throwAnException(..))", throwing = "exception")
    public void adviceForExceptionThrowing(Exception exception) {
        System.out.println("###### " + exception.getMessage() + " ######");
    }

}

结果：

INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@5a10411: startup date [Wed Jun 14 15:51:26 EEST 2017]; root of context hierarchy
###### Some message from the exception ######
Exception in thread "main" java.lang.Exception: Some message from the exception

第二个结果：

@Component
@Aspect
public class CustomAspect {

    @Pointcut("execution(* throwAnException(..))")
    private void pointcutForException() {
    }

    @AfterThrowing(pointcut = "pointcutForException()", throwing = "exception")
    public void adviceForExceptionThrowing(Exception exception) {
        System.out.println("###### " + exception.getMessage() + " ######");
    }

}

我们得到：

INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@5a10411: startup date [Wed Jun 14 15:54:38 EEST 2017]; root of context hierarchy
Exception in thread "main" java.lang.Exception: Some message from the exception
    at blog.codingideas.aspects.SomeBean.throwAnException(SomeBean.java:13)
    at blog.codingideas.aspects.SomeBean$$FastClassBySpringCGLIB$$97c62a5f.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:62)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
    at blog.codingideas.aspects.SomeBean$$EnhancerBySpringCGLIB$$985c5826.throwAnException(<generated>)
    at blog.codingideas.ApplicationMain.main(ApplicationMain.java:13)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
###### Some message from the exception ######

Answer 1

您的代码按预期工作。在抛出异常后执行了@AfterThrown建议。

棘手的是System.out.println。它称引擎盖下的PrintStream。这是一个缓冲流。缓冲流在填满之后或在显式调用flush时写入输出（控制台）。

因此，在您的情况下，它取决于堆栈填充量的内部动态以及在其他线程打印的异常堆栈跟踪之前能够执行多少打印语句。

P.S。尝试几次运行您的每个解决方案，您就会发现这一点在主堆栈跟踪之前和之后以随机顺序打印###### Some message from the exception ######。

@AfterThrowing在Spring中有不同的行为

1 个答案: