[Spring] 간단한 주문 시스템 예제4 - AppConfig 스프링 기반으로 변경

- 드디어 스프링으로 변경해보기

 

 

 

AppConfig.java

package com.hello.core;

import com.hello.core.Order.OrderService;
import com.hello.core.Order.OrderServiceImpl;
import com.hello.core.discount.DiscountPolicy;
import com.hello.core.discount.RateDiscountPolicy;
import com.hello.core.member.MemberRepository;
import com.hello.core.member.MemberService;
import com.hello.core.member.MemberServiceImpl;
import com.hello.core.member.MemoryMemberRepository;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class AppConfig {
            
   @Bean
    public MemberService memberService(){
        return new MemberServiceImpl(memberRepository());
    }
    
    @Bean
    public MemberRepository memberRepository() {
        return new MemoryMemberRepository();
    }

    @Bean
    public OrderService orderService(){
        return new OrderServiceImpl(memberRepository(),  discountPolicy());
    }

    @Bean 
    public DiscountPolicy discountPolicy(){
       ///return new FixDiscountPolicy();
        return new RateDiscountPolicy();
    }

}

 

- @Configuration : AppConfig에 설정을 구성한다는 뜻

- @Bean : @Bean이 붙은 메소드들은 스프링 컨테이너에 등록됨

 

 

 

MemberApp.java / 스프링 컨테이너 적용

package com.hello.core;
import com.hello.core.member.Grade;
import com.hello.core.member.Member;
import com.hello.core.member.MemberService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MemberApp {
    public static void main(String[] args) {

		///MemberService memberService = new MemberServiceImpl();

  		//Appaonfig  사용
		////AppConfig appConfig = new AppConfig();
		////MemberService memberService = appConfig.memberService();
                                      
        //스프링 컨테이너 적용
        ApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);                                                                                       
        MemberService memberService = applicationContext.getBean("memberService", MemberService.class);

        Member member = new Member(1L, "memberA", Grade.VIP);
        memberService.join(member);
        Member findMember = memberService.findMember(1L);
        System.out.println("new member = " + member.getName());
        System.out.println("find Member = " + findMember.getName());
    }
}

 

OrderApp.java / 스프링 컨테이너 적용

package com.hello.core;

import com.hello.core.Order.Order;
import com.hello.core.Order.OrderService;
import com.hello.core.member.Grade;
import com.hello.core.member.Member;
import com.hello.core.member.MemberService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class OrderApp {

    public static void main(String[] args) {
        
        ///MemberService memberService = new MemberServiceImpl();
        ///OrderService orderService = new OrderServiceImpl();
        ///OrderService orderService = new OrderServiceImpl();
        
        //AppConfig사용
        //// AppConfig appConfig = new AppConfig();
        ////MemberService memberService = appConfig.memberService();
        ////OrderService orderService =  appConfig.orderService();
        
        //스프링 컨테이너 적용
        ApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);
        MemberService memberService = applicationContext.getBean("memberService", MemberService.class);
        OrderService orderService = applicationContext.getBean("orderService", OrderService.class);

        long memberId = 1L;
        Member member = new Member(memberId, "memberA", Grade.VIP);
        memberService.join(member);

        Order order = orderService.createOrder(memberId,"itemA",20000);

        System.out.println("order = " + order);
        System.out.println("calculatePrice = " + order.calculatePrice());
    }
}

- ApplicationContext : 스프링 컨테이너

- 스프링 컨테이너는 @Configuration이 붙은 AppConfig를 설정 정보로 사용하고 @Bean이 붙은 메소드들을 모두 호출하여 반환된 객체를 스프링 컨테이너에 등록

- .getBean()은 @Bean이 붙은 메소드의 명을 스프링 빈의 이름으로 사용

- 이전에는 필요한 객체를 AppConfig를 사용해 직접 조회했지만 이제부터는 스프링 컨테이너를 통해 applicationContext.getBean() 메소드로 필요한 스프링 빈을 찾음

 

 

실행시켜보면 이전과 결과값은 같으나 스프링 어쩌구 크레이팅 어쩌고 싱글톤 빈어쩌고 하는걸 확인할수 있음