Propiedades de la aplicación y perfiles

application.properties frente a application.yml

# application.properties:
server.port=8080
spring.datasource.url=jdbc:postgresql://localhost/mydb
spring.jpa.hibernate.ddl-auto=validate

# Equivalent application.yml:
server:
  port: 8080
spring:
  datasource:
    url: jdbc:postgresql://localhost/mydb
  jpa:
    hibernate:
      ddl-auto: validate

Inyectar valores con @Value

@Service
public class PricingService {
    @Value("${pricing.vat-rate:0.20}")
    private double vatRate;
    @Value("${app.name}")
    private String appName;
}

@ConfigurationProperties para un enlace con tipos seguros

@ConfigurationProperties(prefix = "app.mail")
public record MailProperties(
    @NotBlank String host,
    @Min(1) @Max(65535) int port,
    boolean ssl
) {}
// Bind in Spring Boot 3: @EnableConfigurationProperties(MailProperties.class)

Perfiles: definir entornos

# application-dev.properties (active when profile=dev):
spring.datasource.url=jdbc:h2:mem:testdb
logging.level.com.example=DEBUG

# application-prod.properties (active when profile=prod):
spring.datasource.url=jdbc:postgresql://prod-db/app
logging.level.com.example=WARN

Activar perfiles

# application.properties:
spring.profiles.active=dev
# Or environment variable:
export SPRING_PROFILES_ACTIVE=prod
# Or JVM argument:
java -Dspring.profiles.active=prod -jar app.jar

@Profile en los beans

@Configuration
public class DataSourceConfig {
    @Bean @Profile("dev")
    public DataSource h2DataSource() { return new EmbeddedDatabaseBuilder().build(); }
    @Bean @Profile("prod")
    public DataSource postgresDataSource() { return DataSourceBuilder.create().url(prodUrl).build(); }
}

Grupos de perfiles (Spring Boot 2.4+)

# application.properties:
spring.profiles.group.production=prod,metrics,cloud

Configuración externalizada con variables de entorno

# application.properties:
spring.datasource.url=${DB_URL}
spring.datasource.username=${DB_USER}
spring.datasource.password=${DB_PASS}

Prioridad de sobrescritura de propiedades

Cifrado de propiedades sensibles con Jasypt

# application.properties:
spring.datasource.password=ENC(k9r/2dfhXPQz+2jR8yzUYw==)
# JVM arg:
java -Djasypt.encryptor.password=masterSecret -jar app.jar

Archivos YAML con varios documentos

server:
  port: 8080
---
spring:
  config:
    activate:
      on-profile: prod
server:
  port: 443

Comprobación rápida

Resumen