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Spring AOP 学习笔记之 Advice详解

article 2026/1/22 22:30:41

学习材料：https://docs.spring.io/spring-framework/reference/core/aop/ataspectj/advice.html

1. 什么是 Advice（通知）

定义：Advice 是 AOP 的核心概念之一，表示在特定的连接点（Join Point）上执行的代码逻辑。
作用：通过 Advice，可以在方法调用前后、异常抛出时等位置插入自定义逻辑。

2. Advice 的类型

Spring AOP 提供了以下几种类型的 Advice：

2.1 @Before Advice

@Before 注解用于声明前置通知（Before Advice），即在目标方法执行之前执行自定义逻辑。
使用场景：适用于需要在方法执行前进行某些操作的场景，例如日志记录、权限检查等。
参数：@Before 注解可以接受一个切入点表达式，用于指定哪些方法执行前需要应用该Advice。
方法签名：@Before 方法可以有参数，但这些参数必须是Spring AOP支持的参数类型，例如 JoinPoint、ProceedingJoinPoint（仅用于 @Around）、JoinPoint.StaticPart 等。

Pointcut表达式包含在注解里的liline版示例：

@Aspect
public class BeforeExample {@Before("execution(* com.xyz.dao.*.*(..))")public void doAccessCheck() {// ...}
}

Before注解里包含的是Pointcut的signature，真正的Pointcut表达式在@Pointcut注解里定义。

@Aspect
public class BeforeExample {@Before("com.xyz.CommonPointcuts.dataAccessOperation()")public void doAccessCheck() {// ...}
}@Aspect
public CommonPointcuts {@Pointcut("execute * com.xyz.dao.*.*(..)")public void dataAccessOperation() {}}

2.2 @AfterReturing, @AfterThrowing, @After Advice

在Spring AOP中，@AfterReturning、@AfterThrowing 和 @After 是三种不同的通知（Advice）类型，用于在连接点（Join Point）的不同阶段执行自定义逻辑。以下是它们的详细说明：

@AfterReturning
作用：在目标方法成功执行并返回结果后执行。
使用场景：适用于需要在方法成功执行后进行日志记录、资源清理等操作的场景。
参数：可以接收返回值作为参数，通过returning属性指定参数名。

    @Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@AfterReturning(pointcut = "log()", returning = "result")public void afterReturning(Object result) {log.info("LogAspect afterReturning ..., result: {}", result);}

@AfterThrowing
作用：在目标方法抛出异常后执行。
使用场景：适用于需要在方法抛出异常时进行异常处理、日志记录等操作的场景。
参数：可以接收异常对象作为参数，通过throwing属性指定参数名。

    @Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@AfterThrowing(pointcut = "log()", throwing = "exception")public void afterThrowing(Exception exception) {log.info("LogAspect afterThrowing ...", exception);}

@After
作用：无论目标方法是否成功执行，都会在方法执行后执行。
使用场景：适用于需要在方法执行后进行资源清理、日志记录等操作的场景，不关心方法的执行结果。
参数：不接收任何特定参数。

@Slf4j
@Aspect
@Component
public class LogAspect {@Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@After("log()")public void after() {log.info("LogAspect after ...");}
}

2.3 @Around Advice

Around Advice 是一种特殊的Advice，它会在匹配的方法执行前后运行。它有机会在方法执行前后执行自定义逻辑，并且可以决定方法是否执行、何时执行以及如何执行。
使用场景：Around Advice通常用于需要在方法执行前后共享状态的场景，例如启动和停止计时器。
最佳实践：总是使用满足需求的最弱形式的Advice。如果Before Advice已经足够满足需求，则不要使用Around Advice。

返回类型：Around Advice方法的返回类型应为Object。
参数：方法的第一个参数必须是ProceedingJoinPoint类型。
执行方法：在Around Advice方法体内，必须调用proceed()方法来执行目标方法。调用proceed()方法时，如果不带参数，会将调用者原始的参数传递给目标方法。

@Slf4j
@Aspect
@Component
public class LogAspect {@Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@Around("log()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {log.info("LogAspect around start ...");long start = System.currentMillis();Object result = joinPoint.proceed();log.info("LogAspect around end ...");long end = System.currentMillis();System.out.println("cost time: " + (end-start) + "ms");return result;}
}

3 Advice的执行顺序

3.0 测试环境

使用的springboot测试依赖如下：

        <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId><version>3.3.6</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><version>3.3.6</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId><version>3.3.6</version></dependency>

下面测试的Aspect准备拦截Controller的方法，Controller代码如下：

@Slf4j
@RestController
public class HelloCtroller {@GetMapping("/hello")public String hello() {log.info("execute method: hello()");return "hello";}@GetMapping("/divide")public Integer divide(@RequestParam("a") Integer a, @RequestParam("b") Integer b) {log.info("execute method: divide(), a: {}, b: {}", a, b);return a/b;}
}

3.1 单个Aspect的各Advice执行顺序

可以看到我们LogAspect的整体代码如下：

@Slf4j
@Aspect
@Component
public class LogAspect {@Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@Around("log()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {log.info("LogAspect around start ...");Object result = joinPoint.proceed();log.info("LogAspect around end ...");return result;}@Before("log()")public void before() {log.info("LogAspect before ...");}@AfterReturning(pointcut = "log()", returning = "result")public void afterReturning(Object result) {log.info("LogAspect afterReturning ..., result: {}", result);}@AfterThrowing(pointcut = "log()", throwing = "exception")public void afterThrowing(Exception exception) {log.info("LogAspect afterThrowing ...", exception);}@After("log()")public void after() {log.info("LogAspect after ...");}
}

3.1.1 方法正常返回的执行顺序

HelloController.hello() 方法会正常执行，并返回String结果。

我们执行 /hello地址的请求：

http://localhost:8080/hello

后台打印的切面日志如下：

2025-04-15T13:58:26.858+08:00 INFO 25536 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 1 ms
2025-04-15T13:58:26.888+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect around start ...
2025-04-15T13:58:26.889+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect before ...
2025-04-15T13:58:26.889+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.ctroller.HelloCtroller : execute method: hello()
2025-04-15T13:58:26.889+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect afterReturning ..., result: hello
2025-04-15T13:58:26.889+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect after ...
2025-04-15T13:58:26.889+08:00 INFO 25536 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect around end ...

调用方法的正常返回顺序如下：

@Around start --> @Before advice --> orginal method --> @AfterReturing --> @After --> @Around end.

3.1.2 方法碰到异常的执行顺序

HelloController.divide(Integer a, Integer b)方法, 当b=0的时候，就会抛出除零异常。

http://localhost:8080/divide?a=2&b=0

执行的Aspect拦截日志如下：

2025-04-15T14:05:03.612+08:00 INFO 25536 --- [nio-8080-exec-5] org.derek.aspect.LogAspect : LogAspect around start ...
2025-04-15T14:05:03.613+08:00 INFO 25536 --- [nio-8080-exec-5] org.derek.aspect.LogAspect : LogAspect before ...
2025-04-15T14:05:03.613+08:00 INFO 25536 --- [nio-8080-exec-5] org.derek.ctroller.HelloCtroller : execute method: divide(), a: 2, b: 0
2025-04-15T14:05:03.613+08:00 INFO 25536 --- [nio-8080-exec-5] org.derek.aspect.LogAspect : LogAspect afterThrowing ...

java.lang.ArithmeticException: / by zero
   at org.derek.ctroller.HelloCtroller.divide(HelloCtroller.java:25) ~[classes/:na]
   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
   at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
   at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
   at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:355) ~[spring-aop-6.1.15.jar:6.1.15]

2025-04-15T14:05:03.620+08:00 INFO 25536 --- [nio-8080-exec-5] org.derek.aspect.LogAspect : LogAspect after ...
2025-04-15T14:05:03.622+08:00 ERROR 25536 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: java.lang.ArithmeticException: / by zero] with root cause

java.lang.ArithmeticException: / by zero

可以看到异常情况下，拦截执行顺序如下：

@Around start --> @Before Advice --> orginal method --> @AfterThrowing --> @After （--> @Around end 因为抛出异常这里不再执行）

3.2 多个Aspect的各Advice的执行顺序

1. 默认执行顺序
在 Spring AOP 中，默认情况下，Aspect 的执行顺序是未定义的。如果多个 Aspect 匹配同一个连接点（Join Point），它们的执行顺序可能会根据依赖注入的顺序、类加载顺序或其他因素动态决定。

2. 通过 @Order 注解控制顺序
可以使用 @Order 注解来显式指定 Aspect 的优先级。
数字越小，优先级越高，越先执行。
示例代码：

import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.annotation.Order;@Aspect
@Order(1) // 优先级最高
public class FirstAspect {// 定义切入点和通知逻辑
}@Aspect
@Order(2) // 次优先级
public class SecondAspect {// 定义切入点和通知逻辑
}

3. 通过实现 Ordered 接口
如果不想使用 @Order 注解，可以实现 org.springframework.core.Ordered 接口，并重写 getOrder() 方法。
示例代码：

import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.Ordered;@Aspect
public class FirstAspect implements Ordered {@Overridepublic int getOrder() {return 1; // 优先级最高}
}@Aspect
public class SecondAspect implements Ordered {@Overridepublic int getOrder() {return 2; // 次优先级}
}

这里为了测试实际的Aspect执行顺序，我们使用注解@Order的方式定义了两个切面：

ControllerAspect.java, 顺序为1.

@Slf4j
@Aspect
@Component
@Order(1) // 优先级，越小越先执行
public class CtrollerAspect {@Pointcut("execution(* org.derek.ctroller.*.*(..))")public void controller() {System.out.println("log");}@Around("controller()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {log.info("around advice start ...");Object proceed = joinPoint.proceed();log.info("around advice end ...");return proceed;}@Before("controller()")public void before() {log.info("before advice ...");}@AfterReturning(pointcut = "controller()", returning = "result")public void afterReturning(Object result) {log.info("afterReturning advice ..., result: {}", result);}@AfterThrowing(pointcut = "controller()", throwing = "exception")public void afterThrowing(Exception exception) {log.info("afterThrowing advice ...", exception);}@After("controller()")public void after() {log.info("after advice ...");}
}

LogAspect.java, 顺序为2.

@Slf4j
@Aspect
@Component
@Order(2)
public class LogAspect {@Pointcut("execution(* org.derek.ctroller.*.*(..))")public void log() {}@Around("log()")public Object around(ProceedingJoinPoint joinPoint) throws Throwable {log.info("LogAspect around start ...");Object result = joinPoint.proceed();log.info("LogAspect around end ...");return result;}@Before("log()")public void before() {log.info("LogAspect before ...");}@AfterReturning(pointcut = "log()", returning = "result")public void afterReturning(Object result) {log.info("LogAspect afterReturning ..., result: {}", result);}@AfterThrowing(pointcut = "log()", throwing = "exception")public void afterThrowing(Exception exception) {log.info("LogAspect afterThrowing ...", exception);}@After("log()")public void after() {log.info("LogAspect after ...");}
}

执行相同的hello方法，调用日志如下：

2025-04-15T13:52:45.672+08:00 INFO 32288 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 0 ms
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.CtrollerAspect : around advice start ...
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.CtrollerAspect : before advice ...
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect around start ...
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect before ...
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.ctroller.HelloCtroller : execute method: hello()
2025-04-15T13:52:45.705+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect afterReturning ..., result: hello
2025-04-15T13:52:45.707+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect after ...
2025-04-15T13:52:45.707+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.LogAspect : LogAspect around end ...
2025-04-15T13:52:45.707+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.CtrollerAspect : afterReturning advice ..., result: hello
2025-04-15T13:52:45.707+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.CtrollerAspect : after advice ...
2025-04-15T13:52:45.707+08:00 INFO 32288 --- [nio-8080-exec-1] org.derek.aspect.CtrollerAspect : around advice end ...

可以看到，多个切面执行顺序如下：

1) @Order（1）的切面方法 @Around start --> @Before Advice

2) @Order（2）的切面方法 @Around start --> @Before Advice

3) 执行原始的方法 original method

4) @Order（2）的切面方法 @AfterReturning/@AfterThrowing --> @After --> @Adround end

5)@Order（1）的切面方法 @AfterReturning/@AfterThrowing --> @After --> @Adround end