Profiles and configuration

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Goal

Structure Spring Boot configuration for multiple environments using profiles, .env files, and @ConfigurationProperties.

Prerequisites

• Spring Security JWT

Profile-specific files

src/main/resources/
  application.properties          # shared defaults
  application-dev.properties      # dev overrides
  application-prod.properties     # prod overrides

application.properties:

spring.application.name=items-api
server.port=8080
jwt.secret=dev-secret-change-in-prod

application-dev.properties:

spring.datasource.url=jdbc:postgresql://localhost:5432/itemsdb
spring.datasource.password=secret
spring.jpa.show-sql=true

application-prod.properties:

spring.datasource.url=jdbc:postgresql://prod-db:5432/itemsdb
spring.datasource.password=${DB_PASSWORD}
spring.jpa.show-sql=false
jwt.secret=${JWT_SECRET}

Type-safe configuration

@ConfigurationProperties(prefix = "jwt")
@Component
public class JwtProperties {
    private String secret;
    private long expirationMs = 3600_000;
    // getters and setters
}

Enable in a @Configuration class:

@Configuration
@EnableConfigurationProperties(JwtProperties.class)
public class AppConfig {}

Using .env with Dotenv

For local development, use a .env file (never committed):

DB_PASSWORD=local-secret
JWT_SECRET=local-jwt-secret

Spring Boot does not load .env by default. Add me.paulschwarz:spring-dotenv:

<dependency>
    <groupId>me.paulschwarz</groupId>
    <artifactId>spring-dotenv</artifactId>
    <version>4.0.0</version>
</dependency>

Or set environment variables in your shell/IDE run config.

Activate a profile

./mvnw spring-boot:run -Dspring-boot.run.profiles=dev
# or
export SPRING_PROFILES_ACTIVE=prod
./mvnw spring-boot:run

Checkpoint

SPRING_PROFILES_ACTIVE=dev ./mvnw spring-boot:run
# → "The following profiles are active: dev"
# → connects to localhost PostgreSQL

Next: Docker and docker-compose — containerize the Spring Boot app.