spring data jpa : Specifications

spring-data-jpa/src/main/java/com/example/springdatajpa/repository/MemberRepository.java

@@ -14,7 +14,7 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Optional;
 
-public interface MemberRepository extends JpaRepository<Member, Long>, MemberRepositoryCustom{
+public interface MemberRepository extends JpaRepository<Member, Long>, MemberRepositoryCustom, JpaSpecificationExecutor<Member>{
 
     List<Member> findByUsernameAndAgeGreaterThan(String username, int age);
 

spring-data-jpa/src/main/java/com/example/springdatajpa/repository/MemberSpec.java

@@ -0,0 +1,33 @@
+package com.example.springdatajpa.repository;
+
+import com.example.springdatajpa.entity.Member;
+import com.example.springdatajpa.entity.Team;
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.util.ObjectUtils;
+
+import javax.persistence.criteria.Join;
+import javax.persistence.criteria.JoinType;
+
+public class MemberSpec {
+
+    public static Specification<Member> teamName(final String teamName) {
+        return (root, query, criteriaBuilder) -> {
+
+            if (ObjectUtils.isEmpty(teamName)) {
+                return null;
+            }
+
+            Join<Member, Team> t = root.join("team", JoinType.INNER);// 회원과 조인
+            return criteriaBuilder.equal(t.get("name"), teamName);
+        };
+    }
+
+    public static Specification<Member> username(final String username) {
+        return (root, query, criteriaBuilder) -> {
+            if (ObjectUtils.isEmpty(username)) {
+                return null;
+            }
+            return criteriaBuilder.equal(root.get("name"), username);
+        };
+    }
+}

spring-data-jpa/src/test/java/com/example/springdatajpa/repository/MemberRepositoryTest.java

@@ -11,6 +11,7 @@ import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Slice;
 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;
 
@@ -310,7 +311,27 @@ public class MemberRepositoryTest {
     @Test
     void callCustom() {
         List<Member> result = memberRepository.findMemberCustom();
+    }
 
+    @Test
+    void specBasic() {
+        // given
+        Team teamA = new Team("teamA");
+        em.persist(teamA);
+
+        Member member1 = new Member("member1", 0, teamA);
+        Member member2 = new Member("member2", 0, teamA);
+        em.persist(member1);
+        em.persist(member2);
+
+        em.flush();
+        em.clear();
+
+        // when
+        Specification<Member> spec = MemberSpec.username("member1").and(MemberSpec.teamName("teamA"));
+        List<Member> result = memberRepository.findAll(spec);
+
+        assertEquals(1, result.size());
     }
 }