SpringContext Environment Arayüzü

Giriş
Şu satırı dahil ederiz.

import org.springframework.core.env.Environment;

Açıklaması şöyle. Yani sadece System.getenv("...") çağrısınu kullanmaz. Bir sürü yere daha bakarak arama yapar.

Properties play an important role in almost all applications, and may originate from a variety of sources: properties files, JVM system properties, system environment variables, JNDI, servlet context parameters, ad-hoc Properties objects, Maps, and so on. The role of the environment object with relation to properties is to provide the user with a convenient service interface for configuring property sources and resolving properties from them. 

getActiveProfiles metodu
Şöyle yaparız.

@Autowired
Environment env;

// If the environment is dev
if(env.getActiveProfiles()[0].equalsIgnoreCase("dev")) {
  ...
}

getProperty metodu
Örnek
Şöyle yaparız.

@SpringBootApplication
public class Application implements CommandLineRunner {

  @Autowired
  private Environment env;

  @Override
  public void run(String... args) throws Exception {

    logger.info("{}", env.getProperty("JAVA_HOME"));
    logger.info("{}", env.getProperty("app.name"));
  }
  ...
}

getRequiredProperty metodu
Şöyle yaparız.

environment.getRequiredProperty("jdbc.driverClassName")