主页 / coding / 问题 / 79582722
Accepted
Alexei
Asked: 2025-04-20 02:42:00 +0800 CST

@Before 建议未被调用

  • 772

Java 8

package com.myproject.javatestmavenbom.module1.aop;

public class Main {
  public static void main(String[] args) {
    UserService userService = new UserService();
    userService.createUser("create new user john", 21);
    userService.deleteUser("john");
  }
}

package com.myproject.javatestmavenbom.module1.aop;

public class UserService {
  public void createUser(String name, int age) {
    System.out.println("UserService: Request to create user: " + name + " | age: " + age);
  }

  public void deleteUser(String name) {
    System.out.println("UserService: Request to delete user: " + name);
  }
}

package com.myproject.javatestmavenbom.module1.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class MyAspect {
  // Before calling any method in the com.myproject.javatestmavenbom.module1.aop.UserService
  @Before("call(* com.myproject.javatestmavenbom.module1.aop.*(..))")
  public void beforeUserServiceMethodCall(JoinPoint joinPoint) {
    System.out.println("MyAspect: Calling a UserService method: " + joinPoint.getSignature().toShortString());
  }
}

但是当我启动应用程序时，我得到以下结果：

UserService: Request to create user: create new user john | age: 21
UserService: Request to delete user: john

那么，为什么方法beforeUserServiceMethodCall不在createUser/之前调用deleteUser？

MyAspect: Calling a UserService method:
aspectj

1 个回答

  1. Best Answer

    在你的切入点中call(* com.myproject.javatestmavenbom.module1.aop.*(..))，.*接近末尾的 可以表示子包、类或方法名。假设它表示类UserService，那么方法名的后续部分.*就缺失了。以下任一方法都可以：

    • call(* com.myproject.javatestmavenbom.module1.aop.*.*(..))- 该包中任何类的任何方法
    • call(* com.myproject.javatestmavenbom.module1.aop..*(..))- 此包或其任何子包中任何类的任何方法（注意双点符号）

    如果您是 AspectJ 新手，请注意，AspectJ 中同时存在call()和execution()切入点，它们分别用于拦截不同的内容。大多数情况下，您需要execution()，但 也有很多有效的用例call()。

    MyAspect: Calling a UserService method: UserService.createUser(..)
UserService: Request to create user: create new user john | age: 21
MyAspect: Calling a UserService method: UserService.deleteUser(..)
UserService: Request to delete user: john
    • -1

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