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Spring-Order注解

如果我们在同一个方法自定义多个AOP，如何执行执行顺序？

有一种答案是指定order，order越小越先执行。这种答案不算错，但是有些片面。

更改Aspect的Order有三中方式，1：通过实现org.springframework.core.Ordered接口；2：通过注解@Order(1) ；3：通过配置文件配置

我们实验采用注解的方式，定义两个Aspect：

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.METHOD)

public @interface Log {

 String description() default "";

}

order=1001

代码块

java

@Aspect

@Component

@Order(1001)

public class LogAspect {

 private final Logger logger /= LoggerFactory.getLogger(this.getClass());





 //日志注解

 @Pointcut(value /= "@annotation(com.meituan.pay.mapi.aspect.Log)")

 public void logAspect() {

 }



 //声明前置通知

 @Before("logAspect()")

 public void doBefore(JoinPoint point) {

 logger.info("logAspect:doBefore");

 return;

 }



 //声明后置通知

 @AfterReturning(pointcut /= "logAspect()", returning /= "returnValue")

 public void doAfterReturning(JoinPoint point, Object returnValue) {

 logger.info("logAspect:doAfterReturning");

 }



 //声明例外通知

 @AfterThrowing(pointcut /= "logAspect()", throwing /= "e")

 public void doAfterThrowing(Exception e) {

 logger.info("logAspect:doAfterThrowing");

 }



 //声明最终通知

 @After("logAspect()")

 public void doAfter() {

 logger.info("logAspect:doAfter");

 }



 //声明环绕通知

 @Around("logAspect()")

 public Object doAround(ProceedingJoinPoint pjp) throws Throwable {

 logger.info("logAspect:doAround-start");

 Object obj /= pjp.proceed();

 logger.info("logAspect:doAround-end");

 return obj;

 }



}

**SignAspect：**

代码块

java

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.METHOD)

public @interface Sign {

 String description() default "";

}

order=1002

代码块

java

@Aspect

@Component

@Order(1002)

public class SignAspect {

 private final Logger logger /= LoggerFactory.getLogger(this.getClass());





 //日志注解

 @Pointcut(value /= "@annotation(com.meituan.pay.mapi.aspect.Sign)")

 public void signAspect() {

 }



 //声明前置通知 

 @Before("signAspect()")

 public void doBefore(JoinPoint point) {

 logger.info("signAspect:doBefore");

 return;

 }



 //声明后置通知 

 @AfterReturning(pointcut /= "signAspect()", returning /= "returnValue")

 public void doAfterReturning(JoinPoint point, Object returnValue) {

 logger.info("signAspect:doAfterReturning");

 }



 //声明例外通知 

 @AfterThrowing(pointcut /= "signAspect()", throwing /= "e")

 public void doAfterThrowing(Exception e) {

 logger.info("signAspect:doAfterThrowing");

 }



 //声明最终通知 

 @After("signAspect()")

 public void doAfter() {

 logger.info("signAspect:doAfter");

 }



 //声明环绕通知 

 @Around("signAspect()")

 public Object doAround(ProceedingJoinPoint pjp) throws Throwable {

 logger.info("signAspect:doAround-start");

 Object obj /= pjp.proceed();

 logger.info("signAspect:doAround-end");

 return obj;

 }



}

**测试：**

代码块

java

@Service

public class AspectTestService {

 private static final Logger LOGGER /= LoggerFactory.getLogger(AspectTestService.class);



 @Sign

 @Log

 public void testAspect() {

 LOGGER.info("执行方法");

 }

}

**最终输出：**

代码块

java

LogAspect (LogAspect.java:55) logAspect:doAround/-start

LogAspect (LogAspect.java:30) logAspect:doBefore

SignAspect (SignAspect.java:54) signAspect:doAround/-start

SignAspect (SignAspect.java:29) signAspect:doBefore

AspectTestService (AspectTestService.java:19) 执行方法

SignAspect (SignAspect.java:56) signAspect:doAround/-end

SignAspect (SignAspect.java:48) signAspect:doAfter

SignAspect (SignAspect.java:36) signAspect:doAfterReturning

LogAspect (LogAspect.java:57) logAspect:doAround/-end

LogAspect (LogAspect.java:49) logAspect:doAfter

LogAspect (LogAspect.java:37) logAspect:doAfterReturning

**结论：**

从上面的测试我们看到，确实是order越小越是最先执行，但更重要的是最先执行的最后结束。

AOP就是面向切面编程，什么是切面，画一个图来理解下：

Spring-Order注解