@Before advice in Spring Boot - Mini Project: Build & Apply

Using @Before Advice in Spring Boot

📖 Scenario: You are building a Spring Boot application that logs a message before any method in a service class runs. This helps track when methods start executing.

🎯 Goal: Create an aspect with @Before advice that logs a message before methods in the MyService class execute.

📋 What You'll Learn

Create a service class called MyService with a method performTask().

Create an aspect class called LoggingAspect.

Add a @Before advice in LoggingAspect that runs before performTask() method.

The advice should log the message "Starting performTask method".

💡 Why This Matters

🌍 Real World

Logging method calls helps monitor application behavior and debug issues in real time.

💼 Career

Understanding AOP and advice like <code>@Before</code> is essential for building maintainable and modular Spring Boot applications.

1

Create the service class with a method

Create a class called MyService with a public method performTask() that returns void and has an empty body.

Spring Boot

public class MyService {
    // Your code here
}

Need a hint?

Define a public class named MyService. Inside it, add a public method performTask with no parameters and void return type.

2

Create the aspect class

Create a class called LoggingAspect and annotate it with @Aspect and @Component.

Spring Boot

import org.springframework.stereotype.Service;

@Service
public class MyService {
    public void performTask() {
        // method body
    }
}

// Your code here

Need a hint?

Import @Aspect and @Component. Annotate the class LoggingAspect with both annotations.

3

Add @Before advice to log before performTask

Inside LoggingAspect, add a method logBefore() annotated with @Before that matches execution of performTask() in MyService. Inside the method, add a line to log the message "Starting performTask method" using System.out.println.

Spring Boot

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

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

Need a hint?

Use @Before with the pointcut expression execution(void MyService.performTask()). Inside the advice method, print the log message.

4

Enable aspect processing in Spring Boot

In your Spring Boot application main class, add the annotation @EnableAspectJAutoProxy above the class declaration to enable aspect support.

Spring Boot

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

@Aspect
@Component
public class LoggingAspect {
    @Before("execution(void MyService.performTask())")
    public void logBefore() {
        System.out.println("Starting performTask method");
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
// Your code here
@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

Need a hint?

Import and add @EnableAspectJAutoProxy above your main application class to activate aspect support.