Implementing Logging with AOP in Spring Boot

Spring Boot is a popular Java-based framework that simplifies web application development. Logging plays a crucial role in application development and debugging processes. In this article, we will explore how to implement logging operations using Aspect-Oriented Programming (AOP) in Spring Boot applications.

What are AspectJ and AOP?

AspectJ is a Java-based AOP (Aspect Oriented Programming) language and framework. It allows you to address various aspects separately, and manage them centrally during software development. AOP enables you to modify or extend the functionality and behavior of your application. AspectJ is a tool developed to facilitate the implementation of AOP principles.

Sample Code Snippet

The sample code snippet includes an AspectJ logging component created to log the entry and exit of methods in controller classes within a specific package in your application. This component employs two different annotations for logging: @Beforeand @AfterReturning.

package com.vet.config;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;

@Aspect
@Controller
public class Logging {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Before("execution(* com.vet.controller.*.* (..))")
    public void logBefore(JoinPoint joinPoint) {
        logger.info("Entering method: {} with arguments: {} ,Class Name:{}", joinPoint.getSignature().getName(), joinPoint.getArgs(), joinPoint.getSignature().getDeclaringTypeName());
    }

    @AfterReturning(pointcut = "execution(* com.vet.controller.*.* (..))", returning = "result")
    public void logAfter(JoinPoint joinPoint, Object result) {
        logger.info("Exiting method: {} with result: {} ,Class Name:{}", joinPoint.getSignature().getName(), result, joinPoint.getSignature().getDeclaringTypeName());
    }
}

This class is annotated as a Spring-managed component (@Controller) and an AspectJ logging component (@Aspect).

The @Before Annotation

The @Before annotation represents a method that is executed before the target method. In the example above, our logBefore method targets the execution(* com.vet.controller.*.* (..)) pointcut using the @Before annotation. This pointcut will match any method in any class within the "com.vet.controller" package.

Inside the logBefore method, information about the targeted method is accessed using the JoinPoint parameter. This information includes details like the method's name, its arguments, and the name of the declaring class. This information is logged using the logger.

The @AfterReturning Annotation

The @AfterReturning annotation represents a method that is executed after the target method has successfully completed. In the example above, our logAfter method targets the execution(* com.vet.controller.*.* (..)) pointcut using the @AfterReturning annotation.

Inside the logAfter method, the JoinPoint and Object parameters are used to obtain information about the targeted method and its return value. This information includes details like the method's name, the return value, and the name of the declaring class. This information is again logged using the logger.

Lastly , you can decide log file type and where should be.

My configuration file : application.properties

logging.file.name=src/main/resources/static/logfile.txt

You can acces the repository from here:

GitHub - Furkan-Ahmet-Ozdemir/Spring-vet: Vet application .