Profiles

Profile-Specific Configuration Files

application.properties          ← Shared config
application-dev.properties     ← Development
application-staging.properties ← Staging
application-prod.properties    ← Production

Activation Methods

# Command line
java -jar app.jar --spring.profiles.active=prod

# Environment variable
SPRING_PROFILES_ACTIVE=prod

# In application.properties
spring.profiles.active=dev

# Programmatically
System.setProperty("spring.profiles.active", "dev");

Profile-Specific Beans

@Configuration
@Profile("dev")
public class DevConfig {
    @Bean
    public DataSource dataSource() {
        return new EmbeddedDatabaseBuilder()
            .setType(EmbeddedDatabaseType.H2)
            .build();
    }
}

@Configuration
@Profile("prod")
public class ProdConfig {
    @Bean
    public DataSource dataSource() {
        return DataSourceBuilder.create()
            .url("jdbc:postgresql://prod-db:5432/mydb")
            .build();
    }
}

Multi-Profile

@Service
@Profile("!test")  // Active in all profiles except test
public class RealPaymentService implements PaymentService { }

@Service
@Profile("test")
public class MockPaymentService implements PaymentService { }

Configuration

• Use properties over YAML for simple configs
• Externalize configuration
• Use profiles for environments
• Validate on startup

Bean Management

• Prefer constructor injection
• Use appropriate scope
• Implement lazy initialization
• Clean up resources

Security

• Use Spring Security
• Implement CSRF protection
• Use method-level security
• Log security events

Key Points

• Understanding Spring Profiles is essential for production systems
• Always consider scalability and maintainability
• Test thoroughly before deploying to production
• Monitor performance and set up alerting

Common Patterns

1. Validation: Always validate input at the boundary
2. Error Handling: Use structured error responses
3. Logging: Log key events for debugging
4. Testing: Unit, integration, and load tests
5. Documentation: Keep docs updated with code changes