Spring AOP：为什么@After 注解在Java、AspectJ 中的@AfterThrowing 之后执行？

Question

我正在学习 AspectJ 注释，我认为 @After 注释在 @AfterThrowing 注释之前执行。但相反，它在它之后执行。为什么？

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Aspect
@Component
@Order(2)
public class MyDemoLoggingAspect {

    @After("execution(* com.luv2code.aopdemo.dao.AccountDAO.findAccounts(..))")
    public void afterFinallyFindAccountsAdvice(JoinPoint theJoinPoint) {
        
        // print out which method we are advising on
        String method = theJoinPoint.getSignature().toShortString();
        System.out.println("\n=====>>> Executing @After (finally) on method: " 
                            + method);
    
    }
    
    @AfterThrowing(
            pointcut="execution(* com.luv2code.aopdemo.dao.AccountDAO.findAccounts(..))",
            throwing="theExc")
    public void afterThrowingFindAccountsAdvice(
                    JoinPoint theJoinPoint, Throwable theExc) {
        
        // print out which method we are advising on
        String method = theJoinPoint.getSignature().toShortString();
        System.out.println("\n=====>>> Executing @AfterThrowing on method: " + method);
        
        // log the exception
        System.out.println("\n=====>>> The exception is: " + theExc);
    
    }
    
    @AfterReturning(
            pointcut="execution(* com.luv2code.aopdemo.dao.AccountDAO.findAccounts(..))",
            returning="result")
    public void afterReturningFindAccountsAdvice(
                    JoinPoint theJoinPoint, List<Account> result) {
        
        // print out which method we are advising on 
        String method = theJoinPoint.getSignature().toShortString();
        System.out.println("\n=====>>> Executing @AfterReturning on method: " + method);
                
        // print out the results of the method call
        System.out.println("\n=====>>> result is: " + result);
        
        // let's post-process the data ... let's modify it :-)
        
        // convert the account names to uppercase
        convertAccountNamesToUpperCase(result);

        System.out.println("\n=====>>> result is: " + result);
        
    }

    private void convertAccountNamesToUpperCase(List<Account> result) {

        // loop through accounts

        for (Account tempAccount : result) {
            
            // get uppercase version of name
            String theUpperName = tempAccount.getName().toUpperCase();
            
            // update the name on the account
            tempAccount.setName(theUpperName);
        }

    }

    @Before("com.luv2code.aopdemo.aspect.LuvAopExpressions.forDaoPackageNoGetterSetter()")
    public void beforeAddAccountAdvice(JoinPoint theJoinPoint) {
        
        System.out.println("\n=====>>> Executing @Before advice on method");    
        
        // display the method signature
        MethodSignature methodSig = (MethodSignature) theJoinPoint.getSignature();
        
        System.out.println("Method: " + methodSig);
        
        // display method arguments
        
        // get args
        Object[] args = theJoinPoint.getArgs();
        
        // loop thru args
        for (Object tempArg : args) {
            System.out.println(tempArg);
            
            if (tempArg instanceof Account) {
                
                // downcast and print Account specific stuff
                Account theAccount = (Account) tempArg;
                
                System.out.println("account name: " + theAccount.getName());
                System.out.println("account level: " + theAccount.getLevel());                              

            }
        }
        
    }
    
}

输出示例：

=====>>>> 以异步方式登录到云端

=====>>> 在方法上执行@Before 建议方法：List com.luv2code.aopdemo.dao.AccountDAO.findAccounts(boolean) 真

=====>>> 执行 API 分析

=====>>> 在方法上执行@AfterThrowing：AccountDAO.findAccounts(..)

=====>>>>例外情况是：java.lang.RuntimeException：不给你喝汤！！！

=====>>> 在方法上执行@After（最后）：AccountDAO.findAccounts(..)

主程序...捕获到异常：java.lang.RuntimeException：没有汤给你！！！

主程序：AfterThrowingDemoApp

无

Answer 1

您问题的答案在您的日志语句中。 After Advice 相当于一个 finally 块

=====>>> 在方法上执行@After（最后）：AccountDAO.findAccounts(..)

Before、AfterThrowing 和 After 类似于以下 java 代码。

public void advice() {
    before();
    try {
        joinPoint();
    } catch (Exception e) {
        afterThrowing();
    } finally {
        after();
    }
}

private void before() {
    System.out.println("Before");
}

private void after() {
    System.out.println("After");
    
}

private void afterThrowing() {
    System.out.println("After throwing");
    
}

public void joinPoint() {
    System.out.println("Performing API analytics");
    throw new RuntimeException();
}

希望对您有所帮助

参考资料

Finally block

After(Finally) Advice

Spring AOP：为什么@After 注解在Java、AspectJ 中的@AfterThrowing 之后执行？

Spring AOP: Why @After annotation executes after @AfterThrowing in Java, AspectJ?

java

aspectj

spring-aop

主程序：AfterThrowingDemoApp