spring data jpa : @Query, return value, dto

spring-data-jpa/src/main/java/com/example/springdatajpa/dto/MemberDto.java

@@ -0,0 +1,13 @@
+package com.example.springdatajpa.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class MemberDto {
+
+    private Long id;
+    private String username;
+    private String teamName;
+}

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

@@ -1,5 +1,6 @@
 package com.example.springdatajpa.repository;
 
+import com.example.springdatajpa.dto.MemberDto;
 import com.example.springdatajpa.entity.Member;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
@@ -13,4 +14,13 @@ public interface MemberRepository extends JpaRepository<Member, Long> {
 
     @Query(name = "Member.findByUsername") // named query 가 있는지 먼저 찾고(domain.methodName) -> query creation
     List<Member> findByUsername(@Param("username") String username);
+
+    @Query("select m from Member m where m.username = :username and m.age = :age")
+    List<Member> findMember(@Param("username") String username, @Param("age") int age);
+
+    @Query("select m.username from Member m")
+    List<String> findUsernameList();
+
+    @Query("select new com.example.springdatajpa.dto.MemberDto(m.id, m.username, t.name) from Member m join m.team t")
+    List<MemberDto> findMemberDto();
 }

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

@@ -1,6 +1,8 @@
 package com.example.springdatajpa.repository;
 
+import com.example.springdatajpa.dto.MemberDto;
 import com.example.springdatajpa.entity.Member;
+import com.example.springdatajpa.entity.Team;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -17,6 +19,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 public class MemberRepositoryTest {
 
     @Autowired MemberRepository memberRepository;
+    @Autowired TeamRepository teamRepository;
 
     @Test
     void testMember() {
@@ -84,4 +87,47 @@ public class MemberRepositoryTest {
 
         assertEquals(m1, result.get(0));
     }
+
+    @Test
+    public void testQuery() {
+        Member m1 = new Member("aaa", 10);
+        Member m2 = new Member("bbb", 20);
+        memberRepository.save(m1);
+        memberRepository.save(m2);
+
+        List<Member> result = memberRepository.findMember("aaa", 10);
+
+        assertEquals(m1, result.get(0));
+    }
+
+    @Test
+    public void findUsernameList() {
+        Member m1 = new Member("aaa", 10);
+        Member m2 = new Member("bbb", 20);
+        memberRepository.save(m1);
+        memberRepository.save(m2);
+
+        List<String> result = memberRepository.findUsernameList();
+
+        for (String s : result) {
+            System.out.println("s = " + s);
+        }
+
+        assertEquals(2, result.size());
+    }
+
+    @Test
+    public void findMemberDto() {
+        Team team = new Team("teamA");
+        teamRepository.save(team);
+
+        Member m1 = new Member("aaa", 10);
+        m1.setTeam(team);
+        memberRepository.save(m1);
+
+        List<MemberDto> result = memberRepository.findMemberDto();
+
+        assertEquals("aaa", result.get(0).getUsername());
+        assertEquals("teamA", result.get(0).getTeamName());
+    }
 }