[JPA] Spring, JPA Service 구성

Spring과 JPA를 사용하여 서비스 레이어를 구성할 때의 @Transactional 사용법, 의존성 주입 방법, 그리고 테스트 케이스 작성에 대해 설명합니다.

1. @Transactional

Service 를 구성할 때, @Transactional 을 설정할 때, readOnly=true 를 설정하기 귀찮을 때가 있다. 해결하는 방법은, 클래스 상단에

@Transactional(readOnly=true)

를 작성하고, 변경이 필요한 매소드 위에 @Transactional 을 추가한다.

2. 의존성 주입 방법

의존성을 주입하는 가장 좋은 방법은, 생성자로 의존성을 주입하는 것을 권장한다.

[최종 형태]

package jpabook.jpashop.service;

import jpabook.jpashop.domain.Member;
import jpabook.jpashop.repository.MemberRepository;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service
@Transactional(readOnly = true)
@RequiredArgsConstructor
public class MemberService {

    private final MemberRepository memberRepository;

    // 회원 가입
    @Transactional
    public Long join(Member member) {

        validateDuplicateMember(member);

        memberRepository.save(member);

        return member.getId();
    }

    private void validateDuplicateMember(Member member) {
        // Exception
        List&lt;Member&gt; findMembers = memberRepository.findByName(member.getName());

        if(!findMembers.isEmpty()) {
            throw new IllegalStateException("이미 존재하는 회원입니다.");
        }
    }

    // 회원 전체 조회
    public List&lt;Member&gt; findMembers() {
        return memberRepository.findAll();
    }

    public List&lt;Member&gt; findOne(Long memberId) {
        return memberRepository.findAll();
    }
}

3. Test Case 작성하기

package jpabook.jpashop.service;

import jpabook.jpashop.domain.Member;
import jpabook.jpashop.repository.MemberRepository;
import junit.framework.TestCase;
import org.assertj.core.api.Assertions;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Transactional;

import javax.persistence.EntityManager;

@RunWith(SpringRunner.class)
@SpringBootTest
@Transactional
public class MemberServiceTest extends TestCase {

    @Autowired MemberService memberService;
    @Autowired MemberRepository memberRepository;
    @Autowired
    EntityManager em;

    @Test
    public void 회원가입() throws Exception {

        Member member = new Member();
        member.setName("kim99");

        Long savedId = memberService.join(member);

        em.persist(member);

//        em.flush();

        Assertions.assertThat(savedId).isEqualTo(member.getId());

    }
    @Test(expected = IllegalStateException.class)
    public void 중복_회원_예외() throws Exception {

        Member member1 = new Member();
        member1.setName("kim1");

        Member member2 = new Member();
        member2.setName("kim1");

        memberService.join(member1);
        memberService.join(member2);

        Assert.fail("회원 중복 미발생");

    }
}

이것도 읽어보세요