@After and @AfterReturning in Spring Boot - Mini Project: Build & Apply

Using @After and @AfterReturning in Spring Boot

📖 Scenario: You are building a simple Spring Boot application that logs messages after a service method runs. This helps track when methods finish and what results they return.

🎯 Goal: Create an aspect class that uses @After to log a message after a method runs, and @AfterReturning to log the returned value from the method.

📋 What You'll Learn

Create a service class with a method getMessage() that returns a string

Create an aspect class with @After advice that logs after getMessage() runs

Add @AfterReturning advice in the aspect to log the returned string from getMessage()

Use Spring AOP annotations and proper pointcut expressions

💡 Why This Matters

🌍 Real World

Logging method execution and returned values helps monitor application behavior and debug issues in real Spring Boot applications.

💼 Career

Understanding Spring AOP annotations like @After and @AfterReturning is essential for backend developers working with Spring Boot to implement cross-cutting concerns like logging and auditing.

1

Create the service class with getMessage() method

Create a Spring service class called SimpleService with a public method getMessage() that returns the string "Hello from service".

Spring Boot

import org.springframework.stereotype.Service;

@Service
public class SimpleService {
    // Your code here
}

Need a hint?

Use @Service annotation and define getMessage() to return the exact string.

2

Create the aspect class with @After advice

Create an aspect class called LoggingAspect annotated with @Aspect and @Component. Add an @After advice method called afterGetMessage() that runs after SimpleService.getMessage() and logs the message "Method getMessage() finished".

Spring Boot

import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

@Aspect
@Component
public class LoggingAspect {
    // Your code here
}

Need a hint?

Use the pointcut expression execution(* SimpleService.getMessage(..)) to target the method.

3

Add @AfterReturning advice to log the returned value

In the LoggingAspect class, add an @AfterReturning advice method called afterReturningGetMessage() that runs after SimpleService.getMessage() returns. Capture the returned string in a parameter called result and log "Returned message: " followed by the result.

Spring Boot

import org.aspectj.lang.annotation.AfterReturning;

@Aspect
@Component
public class LoggingAspect {
    @After("execution(* SimpleService.getMessage(..))")
    public void afterGetMessage() {
        System.out.println("Method getMessage() finished");
    }

    // Your code here
}

Need a hint?

Use @AfterReturning with pointcut and returning attributes to capture the returned value.

4

Complete the Spring Boot application setup

Add the @SpringBootApplication annotation to a class called Application with a main method that runs the Spring application using SpringApplication.run(Application.class, args).

Spring Boot

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {
    // Your code here
}

Need a hint?

Use @SpringBootApplication and a main method to start the app.