🌱 Spring Boot Introduction

A hands-on project focused on learning Spring Beans and Dependency Injection concepts.

🎯 What I Learned

• Spring Beans lifecycle and configuration
• Dependency Injection (Constructor, Setter, Field)
• IoC Container and Component Scanning
• Spring Profiles for environment-specific configurations
• Best practices for enterprise applications

🚀 Quick Start

git checkout master  # Main code is in master branch

# Run using IntelliJ IDEA (Recommended)
 1. Click Run button in IntelliJ
 2. Or use Run Configuration with profile arguments

# Alternative: Set profile in application.properties
 spring.profiles.active=dev

            OR

# Run with default profile
mvn spring-boot:run

# Run with specific profile
mvn spring-boot:run -Dspring-boot.run.profiles=dev
mvn spring-boot:run -Dspring-boot.run.profiles=prod

💻 Technologies

• Java | Spring Boot | Maven
• Spring Core (IoC & DI) | REST APIs

📂 Project Structure

src/main/java/com/springboot/introduction/
├── IntroductionToSpringbootApplication.java  # Main Spring Boot class
├── AppConfig.java                            # Bean configuration
├── Apple.java                                # Bean example with lifecycle
├── DB.java & ProdDB.java                     # Database interface & implementation
├── DBService.java & DevDB.java               # Service layer with DI
└── resources/application.properties          # App configuration

🔧 Core Concepts Demonstrated

Bean Lifecycle Example

@Component
public class Apple {
     void eatApple() {
        System.out.println("I am eating the apple");
    }

    @PostConstruct
    void callThisBeforeAppleIsUsed() {
        System.out.println("Creating the apple before use");
    }
    
    @PreDestroy
    void callThisBeforeDestroy() {
        System.out.println("Destroying the Apple bean");
    }
}

Spring Profiles Example

@Component
@ConditionalOnProperty(name = "deploy.env", havingValue = "development")
public class DevDB implements DB {

    public String getData() {
        return "Dev Data";
    }

}

@Component
@ConditionalOnProperty(name = "deploy.env", havingValue = "production")
public class ProdDB implements DB{

    public String getData() {
        return "Prod Data";
    }
}

Dependency Injection Example

@Service
public class DBService {

    @Autowired
    final private DB db;

    public DBService(DB db) {
        this.db = db;
    }
    String getData() {
        return db.getData();
    }

}

🌟 Key Benefits Learned

• Loose Coupling - Easy to maintain and test
• Environment-specific Configuration - Different profiles for dev/prod
• Reusable Components - Beans managed by Spring
• Clean Architecture - Separation of concerns

📝 Project Structure

• main branch: Documentation
• master branch: Complete Spring Boot code

👨‍💻 Developer

Mansi Arora - Learning Spring Boot fundamentals

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