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Advice分类Apsect中不同类型Advice执行顺序
Aspect中Advice执行顺序
Aspect1为高优先级，Aspect2为低优先级
Aspect1为低优先级，Aspect2为高优先级
本文主要验证Spring AOP中Advice的执行顺序问题。(Spring版本: 5.3.23)
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Advice分类Spring AOP中Advice可分为如下五类:
@Around@Before@AfterReturning@AfterThrowing@After
Advice相关概念参考
Apsect中不同类型Advice执行顺序package sakura.springinaction;
@SpringBootApplication
@EnableAspectJAutoProxy
public class MySpringApplication {
public static void main(String[] args) {
SpringApplication.run(MySpringApplication.class, args);
}
}
package sakura.springinaction.controller;
@Controller
@Slf4j
public class IndexController {
@GetMapping("/time")
@ResponseBody
public String time() {
LocalDateTime now = LocalDateTime.now();
String nowTime = now.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
log.info("Current time: " + nowTime);
return nowTime;
}
}
Apsect1@Slf4j
@Component
@Aspect
public class Aspect1 {
// 定义 Point Cut 切面
@Pointcut("execution(public * sakura.springinaction.controller.*.*(..))")
public void controllerLayer() {
}
// 定义Advice
@Before("controllerLayer()")
private void beforeAdvice2() {
log.info("Aspect_1 # @Before");
}
@After("controllerLayer() && @annotation(getMapping)")
private void afterAdvice1(GetMapping getMapping) {
log.info("Aspect_1 # @afterAdvice" + " path: " + Arrays.toString(getMapping.value()));
}
@AfterReturning(pointcut = "controllerLayer()", returning = "val")
private void afterReturningAdvice(Object val) {
log.info("Aspect_1 # @AfterReturning" + " returnValue: " + val);
}
@AfterThrowing(pointcut = "controllerLayer()", throwing = "thrower")
private void afterThrowingAdvice(Throwable thrower) {
log.info("Aspect_1 # @AfterThrowing" + " thrower: " + thrower.getClass().getName());
}
@Around("controllerLayer() && @annotation(getMapping)")
private Object aroundAdvice(ProceedingJoinPoint pjp, GetMapping getMapping) throws Throwable {
// Around 前置处理
Stopwatch stopwatch = Stopwatch.createStarted();
log.info("Aspect_1 # @Around-Before" + " methodName: " + pjp.getSignature().getName() + ", path: " + Arrays.toString(getMapping.value()));
Object result = pjp.proceed();
// Around 后置处理
log.info("Aspect_1 # @Around-After" + " methodName: " + pjp.getSignature().getName() + ", runTime: " + stopwatch.elapsed(TimeUnit.NANOSECONDS));
return result;
}
}
在 发起请求(http://localhost:8080/time) 后，日志输出如图:
在同一个切面(Apsect)定义中对于同一个Join Point而言，不同类型的Advice执行先后顺序依次是:
@Around 前置处理@Before@AfterReturning/@AfterThrowing@After@Around 后置置处理优先级说明：
- 对于进入
Join Point的Advice而言(比如:@Around前置处理,@Before)，优先级越高，越先执行；- 对于从
Join Point出来的Advice而言(比如:@Around后置处理,@After)，优先级越高，越后执行；- 优先级从高到低依次为:
@Around,@Before,@After,@AfterReturning,@AfterThrowing；
PS:
如果在同一个切面(
Apsect)中定义了两个同类型的Advice(比如定义两个@Before), 对于某个Join Point而言这两个Advice都匹配，那么这两个Advice执行的先后顺序是无法确定的。
Aspect中Advice执行顺序问： 当不同的Aspect中的Advice 都匹配到了同一个Join Point，那么那个Aspect中的Advice 先执行，那个后执行呢？
答： 不确定 ,但是可以通过在class上添加注解@Order指定优先级确定执行顺序(参考文档)
Aspect1为高优先级，Aspect2为低优先级Aspect1 类似，再定义一个切面类Aspect2,如下package sakura.springinaction.advice;
import org.springframework.core.annotation.Order;
@Slf4j
@Component
@Aspect
@Order(2)
public class Aspect2 {
// 定义Advice
@Before("sakura.springinaction.advice.Aspect1.controllerLayer()")
private void beforeAdvice2() {
log.info("Aspect_2 # @Before");
}
@After("sakura.springinaction.advice.Aspect1.controllerLayer() && @annotation(getMapping)")
private void afterAdvice1(GetMapping getMapping) {
log.info("Aspect_2 # @afterAdvice" + " path: " + Arrays.toString(getMapping.value()));
}
@AfterReturning(pointcut = "sakura.springinaction.advice.Aspect1.controllerLayer()", returning = "val")
private void afterReturningAdvice(Object val) {
log.info("Aspect_2 # @AfterReturning" + " returnValue: " + val);
}
@AfterThrowing(pointcut = "sakura.springinaction.advice.Aspect1.controllerLayer()", throwing = "thrower")
private void afterThrowingAdvice(Throwable thrower) {
log.info("Aspect_2 # @AfterThrowing" + " thrower: " + thrower.getClass().getName());
}
@Around("sakura.springinaction.advice.Aspect1.controllerLayer() && @annotation(getMapping)")
private Object aroundAdvice(ProceedingJoinPoint pjp, GetMapping getMapping) throws Throwable {
Stopwatch stopwatch = Stopwatch.createStarted();
log.info("Aspect_2 # @Around-Before" + " methodName: " + pjp.getSignature().getName() + ", path: " + Arrays.toString(getMapping.value()));
Object result = pjp.proceed();
log.info("Aspect_2 # @Around-After" + " methodName: " + pjp.getSignature().getName() + ", runTime: " + stopwatch.elapsed(TimeUnit.NANOSECONDS));
return result;
}
}
Aspect1 添加@Order注解指定优先级，如下@Slf4j
@Component
@Aspect
@Order(1)
public class Aspect1 {
//...
}
此时，Aspect1的优先级比Aspect2的优先级高。
实验结果如下:
说明：
高优先级的
Aspect1中的@Around前置处理和@Before先于低优先级的Aspect2执行，而@AfterReturning,@After和@Around后置处理，则低优先级的Aspect2先执行。
Aspect1为低优先级，Aspect2为高优先级Aspect中@Order注解优先级,如下:@Slf4j
@Component
@Aspect
@Order(2)
public class Aspect1 {
//...
}
@Slf4j
@Component
@Aspect
@Order(1)
public class Aspect2 {
//...
}
实验结果如下:
Aspect中的Advice 都匹配到了同一个Join Point，不同Aspect中的Advice 执行顺序不确定。Aspect类上添加注解@Order指定优先级，确定执行顺序，执行顺序满足如下规律
@Around前置处理 和@Before两种Advice而言，所在的Aspect优先级越高，越先执行@AfterReturning，@AfterThrowing,@After和@Around后置处理 类型的Advice而言，所在的Aspect优先级越高，越后执行本文主要目的是记录学习过程,加深对知识点理解; 如有行文有误,望指正。