@Value("${springtour.domain.name:springtour.io}")
private String springtourDomain;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class PropertiesComponent {
  private final List<String> bootStrapServers;
  private final String checkoutTopic;
  private final String reservationTopic;
  private final Integer ackLevel;

  public PropertiesComponent(
      @Value("${springtour.kafka.bootstrap-servers}") List<String> bootStrapServers,
      @Value("${springtour.kafka.topic.checkout}") String checkoutTopic,
      @Value("${springtour.kafka.topic.reservation}") String reservationTopic,
      @Value("${springtour.kafka.ack-level}") Integer ackLevel) {
    this.bootStrapServers = bootStrapServers;
    this.checkoutTopic = checkoutTopic;
    this.reservationTopic = reservationTopic;
    this.ackLevel = ackLevel;

    System.out.println("---" + this.bootStrapServers);  // [10.1.1.100, 10.1.1.101, 10.1.1.102]
    System.out.println("---" + this.checkoutTopic);
    System.out.println("---" + this.reservationTopic);
    System.out.println("---" + this.ackLevel);  // 1
  }
}

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.springframework.boot.context.properties.ConfigurationProperties;

import java.util.List;

@ToString
@Getter
@Setter
@ConfigurationProperties(prefix = "springtour.kafka") // springtour.kafka 로 시작하는 모든 키는 KafkaProperties 자바 빈에 주입됨
public class KafkaProperties {
  // 프로퍼티 키 이름에 포함된 하이픈은 카멜 표기법으로 변경
  private List<String> bootStrapServers;
  private Integer ackLevel;
  // . 으로 구분된 프로퍼티 키를 주입하려면 하위 클래스로 구분
  private Topic topic;

  @ToString
  @Getter
  @Setter
  public static class Topic {
    private String checkout;
    private String reservation;
  }
}

@SpringBootApplication
@ConfigurationPropertiesScan("com.assu.study.chap06")
public class Chap06Application {
  ...
}

@RestController
public class HotelRoomController {

  KafkaProperties kafkaProperties;

  public HotelRoomController(KafkaProperties kafkaProperties) {
    this.kafkaProperties = kafkaProperties;
  }

  @GetMapping(path = "/hotels/{hotelId}/rooms/{roomNumber}")
  public HotelRoomResponse getHotelRoomByPeriod(
          ClientInfo clientInfo,
          @PathVariable Long hotelId,
          @PathVariable HotelRoomNumber roomNumber,
          @RequestParam(value = "fromDate", required = false) @DateTimeFormat(pattern = "yyyyMMdd") LocalDate fromDate,
          @RequestParam(value = "toDate", required = false) @DateTimeFormat(pattern = "yyyyMMdd") LocalDate toDate
  ) {

    System.out.println("--------" + kafkaProperties.getAckLevel());
    System.out.println("--------" + kafkaProperties.getTopic().getCheckout());
    System.out.println("--------" + kafkaProperties.getTopic().getReservation());
    System.out.println("--------" + kafkaProperties.getBootstrapServers());
  }
}

@Profile(value={"dev", "stage", "local"})
@Configuration  // 자바 설정 클래스
public class Test {
  @Bean
  public String testName() {
    return "test";
  }
}

@Bean
@Profile("prod")
public String testName() {
  return "test";
}

@Bean
@Profile("!prod")
public String testName() {
  return "test";
}

public interface EmailService {
  boolean sendEmail(EmailAddress emailAddress);
}

package com.assu.study.chap06.domain.email;

import lombok.Getter;

import java.util.Objects;

// DTO
@Getter
public class EmailAddress {
  private static final String AT = "@";

  private final String name;
  private final String domainPart;
  private final String localPart;

  public EmailAddress(String name, String domainPart, String localPart) {
    this.name = name;
    this.domainPart = domainPart;
    this.localPart = localPart;
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    if (Objects.nonNull(name)) {
      sb.append(name).append(" ");
    }
    return sb.append("<").append(localPart).append(AT).append(domainPart).append(">").toString();
  }
}

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Service;

@Service
@Profile("!email")  // 프로파일 중 email 값이 없는 애플리케이션에서는 DummyEmailService 구현체를 스프링 빈으로 생성
public class DummyEmailService implements EmailService {
  @Override
  public boolean sendEmail(EmailAddress emailAddress) {
    System.out.println("dummy email: " + emailAddress.toString());
    return true;
  }
}

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Service;

@Service
@Profile("email")  // 프로파일 중 email 값이 있는 애플리케이션에서는 AwsEmailService 구현체를 스프링 빈으로 생성
public class AWSEmailService implements EmailService {
  @Override
  public boolean sendEmail(EmailAddress emailAddress) {
    System.out.println("aws email: " + emailAddress.toString());
    return true;
  }
}

@RestController
public class EmailController {
  private final EmailService emailService;

  public EmailController(EmailService emailService) {
    this.emailService = emailService;
  }

  @PostMapping("/hotels/{hotelId}/rooms/{roomNumber}/reservations/{reservationId}/send-email")
  public ResponseEntity<Void> sendEmail(@PathVariable Long hotelId,
                                        @PathVariable String roomNumber,
                                        @PathVariable Long reservationId) {
    emailService.sendEmail(new EmailAddress("Assu", "assu", "google.com"));
    return new ResponseEntity<>(HttpStatus.OK);
  }
}