Spring Boot AOP unable to get annotation parameters

Question

Using Spring Boot v2.2.4.

For my custom AOP annotations I want to get the values given to the annotation of the annotated method. But I am unable to do so.

What I want to be able to do is apply some security annotations where it will limit user access to the method based on the limit allowed by the method and the permissions that the accessing user has. I thought AOP is my best.

Also since I expect heavy usage on this method I would prefer not to use reflection based solutions. I am aware that we can get the method signature from the join point and from there access the annotation values. But I've heard that reflection based solutions are strongly discouraged in production environments.

Annotation

package com.example.demo;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnno {
    public String permissions() default "";
}

Aspect

package com.example.demo;

import java.lang.reflect.Method;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

@Aspect
@Component(value = "aspectO")
public class AspectO {
    @Pointcut("execution(public * *(..))")
    public void anyPublic(){}

    @Pointcut("@annotation(com.example.demo.MyAnno)")
    public void myAnnotation(){}

    @Before("myAnnotation()")
    public void reactNow(JoinPoint jp, MyAnno myAnno) {
        System.out.println("allowed permissions are: "+myAnno.permission);
    }
}

Main class

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        ApplicationContext appCon = SpringApplication.run(DemoApplication.class, args);
        InnerDemoApplication obj = appCon.getBean(InnerDemoApplication.class);
        System.out.println("Howdy");
        obj.name();
        System.out.println(appCon.containsBean("aspectO"));
    }

    /**
     * InnerDemoApplication
     */
    @Component(value = "inDemo")
    public class InnerDemoApplication {
        @MyAnno(permissions = "stuff")
        public void name() {
            System.out.println("inside some method");
        }       
    }

}

The error

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.4.RELEASE)

2020-02-10 00:32:37.304  INFO 22236 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication on kloudone-pc with PID 22236 (/media/data_drive/data/misc/aoptest2/demo/target/classes started by kloudone in /media/data_drive/data/misc/aoptest2/demo)
2020-02-10 00:32:37.307  INFO 22236 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2020-02-10 00:32:37.936  WARN 22236 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'demoApplication': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: error at ::0 formal unbound in pointcut
2020-02-10 00:32:37.945  INFO 22236 --- [           main] ConditionEvaluationReportLoggingListener :

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-02-10 00:32:37.950 ERROR 22236 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'demoApplication': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: error at ::0 formal unbound in pointcut
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:603) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.4.RELEASE.jar:2.2.4.RELEASE]
    at com.example.demo.DemoApplication.main(DemoApplication.java:12) [classes/:na]
Caused by: java.lang.IllegalArgumentException: error at ::0 formal unbound in pointcut
    at org.aspectj.weaver.tools.PointcutParser.parsePointcutExpression(PointcutParser.java:319) ~[aspectjweaver-1.9.5.jar:na]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.buildPointcutExpression(AspectJExpressionPointcut.java:227) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.obtainPointcutExpression(AspectJExpressionPointcut.java:198) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.aspectj.AspectJExpressionPointcut.getClassFilter(AspectJExpressionPointcut.java:177) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.support.AopUtils.canApply(AopUtils.java:226) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.support.AopUtils.canApply(AopUtils.java:289) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.support.AopUtils.findAdvisorsThatCanApply(AopUtils.java:321) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findAdvisorsThatCanApply(AbstractAdvisorAutoProxyCreator.java:126) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findEligibleAdvisors(AbstractAdvisorAutoProxyCreator.java:95) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.getAdvicesAndAdvisorsForBean(AbstractAdvisorAutoProxyCreator.java:76) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.wrapIfNecessary(AbstractAutoProxyCreator.java:347) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessAfterInitialization(AbstractAutoProxyCreator.java:299) ~[spring-aop-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:431) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595) ~[spring-beans-5.2.3.RELEASE.jar:5.2.3.RELEASE]
    ... 14 common frames omitted

Answer 1

You have an advice parameter MyAnno myAnno in reactNow(..) which does not occur in your pointcut. You need to change your code like this (untested, just quickly typing it):

@Pointcut("@annotation(myAnno)")
public void myAnnotation(MyAnno myAnno){}

@Before("myAnnotation(myAnno)")
public void reactNow(JoinPoint jp, MyAnno myAnno) {
    System.out.println("allowed permissions are: " + myAnno.permission);
}

Or simply inline if you do not re-use your pointcut anywhere else:

@Before("@annotation(myAnno)")
public void reactNow(JoinPoint jp, MyAnno myAnno) {
    System.out.println("allowed permissions are: " + myAnno.permission);
}