[스프링 데이터 JPA] 01. 순수 JPA 기반 리포지토리 만들기

예제 도메인 모델

 

Member 엔티티

package study.datajpa.entity;

import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import javax.persistence.*;

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = { "id", "username", "age" })
public class Member {
	@Id
	@GeneratedValue
	@Column(name = "member_id")
	private Long id;
	private String username;
	private int age;
	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "team_id")
	private Team team;

	public Member(String username) {
		this(username, 0);
	}

	public Member(String username, int age) {
		this(username, age, null);
	}

	public Member(String username, int age, Team team) {
		this.username = username;
		this.age = age;
		if (team != null) {
			changeTeam(team);
		}
	}

	public void changeTeam(Team team) {
		this.team = team;
		team.getMembers().add(this);
	}
}

 

Team 엔티티

package study.datajpa.entity;

import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = { "id", "name" })
public class Team {
	@Id
	@GeneratedValue
	@Column(name = "team_id")
	private Long id;
	private String name;
	@OneToMany(mappedBy = "team")
	List<Member> members = new ArrayList<>();

	public Team(String name) {
		this.name = name;
	}
}

 

Member와 Team은 양방향 연관관계

Member.team 이 연관관계의 주인, Team.members 는 연관관계의 주인이 아님,

따라서 Member.team 이 데이터베이스 외래키 값을 변경, 반대편은 읽기만 가능

 

순수 JPA 기반 리포지토리 만들기

 

순수 JPA 기반 리포지토리 - 회원

package study.datajpa.repository;

import org.springframework.stereotype.Repository;
import study.datajpa.entity.Member;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import java.util.List;
import java.util.Optional;

@Repository
public class MemberJpaRepository {
	@PersistenceContext
	private EntityManager em;

	public Member save(Member member) {
		em.persist(member);
		return member;
	}

	public void delete(Member member) {
		em.remove(member);
	}

	public List<Member> findAll() {
		return em.createQuery("select m from Member m", Member.class).getResultList();
	}

	public Optional<Member> findById(Long id) {
		Member member = em.find(Member.class, id);
		return Optional.ofNullable(member);
	}

	public long count() {
		return em.createQuery("select count(m) from Member m", Long.class).getSingleResult();
	}

	public Member find(Long id) {
		return em.find(Member.class, id);
	}
}

 

순수 JPA 기반 리포지토리 - 팀

package study.datajpa.repository;

import org.springframework.stereotype.Repository;
import study.datajpa.entity.Team;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import java.util.List;
import java.util.Optional;

@Repository
public class TeamJpaRepository {
	@PersistenceContext
	private EntityManager em;

	public Team save(Team team) {
		em.persist(team);
		return team;
	}

	public void delete(Team team) {
		em.remove(team);
	}

	public List<Team> findAll() {
		return em.createQuery("select t from Team t", Team.class).getResultList();
	}

	public Optional<Team> findById(Long id) {
		Team team = em.find(Team.class, id);
		return Optional.ofNullable(team);
	}

	public long count() {
		return em.createQuery("select count(t) from Team t", Long.class).getSingleResult();
	}
}

 

순수 JPA 기반 리포지토리 테스트

package study.datajpa.repository;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Transactional;
import study.datajpa.entity.Member;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;

@SpringBootTest
@Transactional
public class MemberJpaRepositoryTest {
	@Autowired
	MemberJpaRepository memberJpaRepository;

	@Test
	public void testMember() {
		Member member = new Member("memberA");
		Member savedMember = memberJpaRepository.save(member);
		Member findMember = memberJpaRepository.find(savedMember.getId());
		assertThat(findMember.getId()).isEqualTo(member.getId());
		assertThat(findMember.getUsername()).isEqualTo(member.getUsername());
		assertThat(findMember).isEqualTo(member); // JPA 엔티티 동일성 보장
	}

	@Test
	public void basicCRUD() {
		Member member1 = new Member("member1");
		Member member2 = new Member("member2");
		memberJpaRepository.save(member1);
		memberJpaRepository.save(member2);
		// 단건 조회 검증
		Member findMember1 = memberJpaRepository.findById(member1.getId()).get();
		Member findMember2 = memberJpaRepository.findById(member2.getId()).get();
		assertThat(findMember1).isEqualTo(member1);
		assertThat(findMember2).isEqualTo(member2);
		// 리스트 조회 검증
		List<Member> all = memberJpaRepository.findAll();
		assertThat(all.size()).isEqualTo(2);
		// 카운트 검증
		long count = memberJpaRepository.count();
		assertThat(count).isEqualTo(2);
		// 삭제 검증
		memberJpaRepository.delete(member1);
		memberJpaRepository.delete(member2);
		long deletedCount = memberJpaRepository.count();
		assertThat(deletedCount).isEqualTo(0);
	}
}

기본 CRUD를 검증한다.