Spring源码-Aspect-AOP执行顺序

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总结摘要
Spring AOP Aspect 执行顺序

源码分析

Advisor 排序规则

  1. Aspect Bean 顺序，根据 Bean 的 Order 注解或其它 Order 标识排序。
  2. Aspect 注解顺序 Around.class，Before.class，After.class，AfterReturning.class，AfterThrowing.class。
  3. 方法名称。

注意事项

  1. After、AfterReturning和AfterThrowing类型较为特殊，优先级越高，生效时机越晚。

以After为例说明。

当声明2个After类型切面，aspect_after1的优先级高于aspect_after2，则两个切面的逻辑等价于如下

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public void aspect_after1 {
    actual_method_maybe_with_other_aspcet();
    after1_feature();
}

public void aspect_after2 {
    actual_method_maybe_with_other_aspcet();
    after2_feature();
}

public void main_aop {
    aspect_after1();
}

最终执行流程为

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aspect_after1()
   |
   |
  \/
aspect_after2()
   |
   |
  \/
actual_method()
   |
   |
  \/
after2_feature()
   |
   |
  \/
after1_feature()

实现

  1. org.springframework.aop.aspectj.annotation.ReflectiveAspectJAdvisorFactory#adviceMethodComparator 对 Aspect Bean 中的 Aspect 方法排序，首先根据注解，其次根据方法名称。
  2. org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator#sortAdvisors 对 Aspect Bean 排序，使用稳定的拓扑排序算法，基于规则 org.springframework.core.annotation.AnnotationAwareOrderComparator#INSTANCE。

验证 

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@Order(1)
@Aspect
@Component
// [SpringAOP][LoggingA]
public class LoggingAAspectSpringBean {}

@Order(10)
@Aspect
@Component
// [SpringAOP][LoggingB]
public class LoggingBAspectSpringBean {}

执行日志

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[SpringAOP][LoggingA] Around begin action: testPublic
[SpringAOP][LoggingA] Before action: testPublic
[SpringAOP][LoggingB] Around begin action: testPublic
[SpringAOP][LoggingB] Before action: testPublic
testPublic
[SpringAOP][LoggingB] AfterReturning action: testPublic
[SpringAOP][LoggingB] After action: testPublic
[SpringAOP][LoggingB] Around end action: testPublic
[SpringAOP][LoggingA] AfterReturning action: testPublic
[SpringAOP][LoggingA] After action: testPublic
[SpringAOP][LoggingA] Around end action: testPublic

LoggingAAspectSpringBean

LoggingBAspectSpringBean

org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator#sortAdvisors

(org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator#findEligibleAdvisors)

(org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator#getAdvicesAndAdvisorsForBean)

END