Spring 5 AOP：不执行建议

Question

Could someone please help me to understand what am I missing here

1. The code works fine if I remove @EnableAspectJAutoProxy from StudentModuleConfig
2. The code also works fine I define advice as @Before("execution(* fi*(..))") with @EnableAspectJAutoProxy and advice works

Problem happens with @Before("execution(* *(..))"), not sure why

Student.java

package com.springpeople.training.assignment.student.domain;

import java.util.Collection;
import java.util.Collections;

import com.springpeople.training.assignment.course.domain.Course;

public class Student {
    private String name;
    private String surname;
    private Collection<Course> enrolledCourses = Collections.emptyList();
    private String userName;

    public Student() {
    }

    public Student(String name, String surname, String userName, Course... enrolledCourses) {
        super();
        this.name = name;
        this.surname = surname;
        this.userName = userName;
        for (Course course : enrolledCourses) {
            this.enrolledCourses.add(course);
        }
    }

    public Student(String name, String surname, String userName) {
        super();
        this.name = name;
        this.surname = surname;
        this.userName = userName;
    }

    @Override
    public String toString() {
        return "Student [name=" + name + ", surname=" + surname + ", enrolledCourses=" + enrolledCourses + ", userName="
                + userName + "]";
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public Collection<Course> getEnrolledCourses() {
        return enrolledCourses;
    }

    public void setEnrolledCourses(Collection<Course> enrolledCourses) {
        this.enrolledCourses = enrolledCourses;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

}

StudentRepository

package com.springpeople.training.assignment.student.repositoy;

import java.util.Collection;

import com.springpeople.training.assignment.course.domain.Course;
import com.springpeople.training.assignment.student.domain.Student;

public interface StudentRepository {
    Collection<Student> findAllStudentByCourse(Course course);
}

StudentRepositoryImpl.java

package com.springpeople.training.assignment.student.repositoy;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Objects;

import com.springpeople.training.assignment.course.domain.Course;
import com.springpeople.training.assignment.student.domain.Student;


public class StudentRepositoryImpl implements StudentRepository {

    public StudentRepositoryImpl() {
        System.out.println("StudentRepositoryImpl constructor invoked");
    }

    public void init() {
        System.out.println("StudentRepositoryImpl.init() invoked");
    }

    public void destroy() {
        System.out.println("StudentRepositoryImpl.destroy() invoked");
    }

    @Override
    public Collection<Student> findAllStudentByCourse(Course course) {
        List<Student> students = new ArrayList<>();
        if (Objects.nonNull(course) && "Spring".equals(course.getName())) {
            students.add(new Student("A", "a", "aa"));
            students.add(new Student("B", "b", "bb"));
        }
        return students;
    }

}

StudentService

package com.springpeople.training.assignment.student.service;

import java.util.Collection;

import com.springpeople.training.assignment.course.domain.Course;
import com.springpeople.training.assignment.student.domain.Student;

public interface StudentService {
    Collection<Student> findAllStudentByCourse(Course course);
}

StudentServiceImpl

package com.springpeople.training.assignment.student.service;

import java.util.Collection;

import org.springframework.beans.factory.annotation.Autowired;

import com.springpeople.training.assignment.course.domain.Course;
import com.springpeople.training.assignment.student.domain.Student;
import com.springpeople.training.assignment.student.repositoy.StudentRepository;

public class StudentServiceImpl implements StudentService {

    private StudentRepository repository;

    public StudentServiceImpl() {
        System.out.println("StudentServiceImpl constructor invoked");
    }

    public StudentServiceImpl(StudentRepository repository) {
        this.repository = repository;
    }

    public void init() {
        System.out.println("StudentServiceImpl.init() invoked");
    }

    public void destroy() {
        System.out.println("StudentServiceImpl.destroy() invoked");
    }

    @Override
    public Collection<Student> findAllStudentByCourse(Course course) {
        return repository.findAllStudentByCourse(course);
    }

    public void setStudentRepository(StudentRepository studentRepositoryBean) {
        repository = studentRepositoryBean;
    }

}

LoggingAspect

package com.springpeople.training.assignment.student.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class LoggingAspect {

    @Before("execution(* *(..))")
    public void logBefore(JoinPoint joinPoint) {
        System.out.println("LoggingAspect.logBefore(): "+joinPoint.getSignature().getName());
    }

}

StudentModuleConfig.java

package com.springpeople.training.assignment.student;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

import com.springpeople.training.assignment.student.aspect.LoggingAspect;
import com.springpeople.training.assignment.student.repositoy.StudentRepository;
import com.springpeople.training.assignment.student.repositoy.StudentRepositoryImpl;
import com.springpeople.training.assignment.student.service.StudentService;
import com.springpeople.training.assignment.student.service.StudentServiceImpl;

@Configuration
@EnableAspectJAutoProxy
public class StudentModuleConfig {

    @Bean
    public StudentRepository getStudentRepositoryBean() {
        return new StudentRepositoryImpl();
    }

    @Bean
    public StudentService getStudentServiceBean() {
        StudentServiceImpl studentServiceImpl = new StudentServiceImpl();
        studentServiceImpl.setStudentRepository(getStudentRepositoryBean());
        return studentServiceImpl;
    }

    @Bean
    public LoggingAspect getLoggingAspectBean() {
        return new LoggingAspect();
    }
}

App2.java

package com.springpeople.training.assignment;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import com.springpeople.training.assignment.course.domain.Course;
import com.springpeople.training.assignment.student.StudentModuleConfig;
import com.springpeople.training.assignment.student.service.StudentService;

public class App2 
{
    public static void main( String[] args ) throws InterruptedException
    {
        ApplicationContext container = new AnnotationConfigApplicationContext(StudentModuleConfig.class);
        StudentService service3 = container.getBean(StudentService.class);
        System.out.println(service3.findAllStudentByCourse(new Course("Spring", 12, "advance")));
    }
}

Exception: Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getStudentRepositoryBean' defined in com.springpeople.training.assignment.student.StudentModuleConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.repositoy.StudentRepository]: Factory method 'getStudentRepositoryBean' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getLoggingAspectBean' defined in com.springpeople.training.assignment.student.StudentModuleConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.aspect.LoggingAspect]: Factory method 'getLoggingAspectBean' threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'getLoggingAspectBean': Requested bean is currently in creation: Is there an unresolvable circular reference? at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590)

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.repositoy.StudentRepository]: Factory method 'getStudentRepositoryBean' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getLoggingAspectBean' defined in com.springpeople.training.assignment.student.StudentModuleConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.aspect.LoggingAspect]: Factory method 'getLoggingAspectBean' threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'getLoggingAspectBean': Requested bean is currently in creation: Is there an unresolvable circular reference? at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getLoggingAspectBean' defined in com.springpeople.training.assignment.student.StudentModuleConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.aspect.LoggingAspect]: Factory method 'getLoggingAspectBean' threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'getLoggingAspectBean': Requested bean is currently in creation: Is there an unresolvable circular reference? at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590)

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.springpeople.training.assignment.student.aspect.LoggingAspect]: Factory method 'getLoggingAspectBean' threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'getLoggingAspectBean': Requested bean is currently in creation: Is there an unresolvable circular reference? at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:582) ... 38 more Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'getLoggingAspectBean': Requested bean is currently in creation: Is there an unresolvable circular reference? at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.beforeSingletonCreation(DefaultSingletonBeanRegistry.java:339) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:215)

Edit If I do the following, it works..

Removed the following from StudentModuleConfig

@Bean
    public LoggingAspect getLoggingAspectBean() {
        return new LoggingAspect();
    }

And added @ComponantScan in the StudentModuleConfig as follows:

@ComponentScan(basePackages= {"com.springpeople.training.assignment.student.aspect"})

But I still have the question why it didn't work if I declare the LoggingAspect as a bean by using @Bean annotation, is this not the way we can create a container managed bean

Answer 1

Avoid trying to instantiate the aspect bean manually, let Spring take care of its lifecycle. So to remove StudentModuleConfig.getLoggingAspectBean() and add @ComponentScan to the class instead is the right thing to do, as you already found out.

Not being a Spring user (I only have a Spring AOP playground project for answering questions like yours), I can only speculate about what might be happening there. But I think that somehow Spring thinks you want to create a regular Spring bean, not knowing that it is an aspect instance, and tries to apply the aspect to it because of your global catch-all pointcut. Thus the mentioned circular reference in the error log. Note that an aspect is not a normal bean even though it is a @Component , eg aspects cannot advise themselves.