feat: Specifications 구현

Spring-JPA/data-jpa/src/main/java/study/datajpa/repository/MemberRepository.java

@@ -7,6 +7,7 @@
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.data.jpa.repository.Lock;
 import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
@@ -18,7 +19,8 @@
 import study.datajpa.dto.MemberDto;
 import study.datajpa.entity.Member;
 
-public interface MemberRepository extends JpaRepository<Member, Long>, MemberRepositoryCustom {
+public interface MemberRepository extends JpaRepository<Member, Long>, MemberRepositoryCustom,
+											JpaSpecificationExecutor<Member> {
 
 	/** 메소드 이름으로 쿼리 생성 **/
 	List<Member> findByUsernameAndAgeGreaterThan(String username, int age);

Spring-JPA/data-jpa/src/main/java/study/datajpa/repository/MemberSpec.java

@@ -0,0 +1,27 @@
+package study.datajpa.repository;
+
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.util.StringUtils;
+
+import jakarta.persistence.criteria.Join;
+import jakarta.persistence.criteria.JoinType;
+import study.datajpa.entity.Member;
+import study.datajpa.entity.Team;
+
+public class MemberSpec {
+
+	public static Specification<Member> teamName(final String teamName) {
+		return (Specification<Member>) (root, query, builder) -> {
+			if (StringUtils.isEmpty(teamName)) {
+				return null;
+			}
+			Join<Member, Team> t = root.join("team", JoinType.INNER); //회원과 조인
+			return builder.equal(t.get("name"), teamName);
+		};
+	}
+
+	public static Specification<Member> username(final String username) {
+		return (Specification<Member>)(root, query, builder) ->
+			builder.equal(root.get("username"), username);
+	}
+}

Spring-JPA/data-jpa/src/test/java/study/datajpa/repository/MemberRepositoryTest.java

@@ -14,6 +14,7 @@
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.jpa.domain.Specification;
 import org.springframework.test.annotation.Rollback;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -285,4 +286,26 @@ public void callCustom() {
 		List<Member> memberCustom = memberRepository.findMemberCustom();
 	}
 
+	@Test
+	public void specBasic() throws Exception {
+		//given
+		Team teamA = new Team("teamA");
+		em.persist(teamA);
+
+		Member m1 = new Member("m1", 0, teamA);
+		Member m2 = new Member("m2", 0, teamA);
+		em.persist(m1);
+		em.persist(m2);
+
+		em.flush();
+		em.clear();
+
+		//when
+		Specification<Member> spec = MemberSpec.username("m1").and(MemberSpec.teamName("teamA"));
+		List<Member> result = memberRepository.findAll(spec);
+
+		//then
+		assertThat(result.size()).isEqualTo(1);
+	}
+
 }