spring data jpa : named query

spring-data-jpa/src/main/java/com/example/springdatajpa/entity/Member.java

@@ -8,6 +8,10 @@ import javax.persistence.*;
 @Getter @Setter
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 @ToString(of = {"id", "username", "age"})
+@NamedQuery(
+        name="Member.findByUsername",
+        query="select m from Member m where m.username = :username"
+)
 public class Member {
 
     @Id @GeneratedValue

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

@@ -48,4 +48,10 @@ public class MemberJpaRepository {
                 .setParameter("age", age)
                 .getResultList();
     }
+
+    public List<Member> findByUsername(String username) {
+        return em.createNamedQuery("Member.findByUsername", Member.class)
+                .setParameter("username", username)
+                .getResultList();
+    }
 }

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

@@ -2,10 +2,15 @@ package com.example.springdatajpa.repository;
 
 import com.example.springdatajpa.entity.Member;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 import java.util.List;
 
 public interface MemberRepository extends JpaRepository<Member, Long> {
 
     List<Member> findByUsernameAndAgeGreaterThan(String username, int age);
+
+    @Query(name = "Member.findByUsername") // named query 가 있는지 먼저 찾고(domain.methodName) -> query creation
+    List<Member> findByUsername(@Param("username") String username);
 }

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

@@ -72,4 +72,16 @@ class MemberJpaRepositoryTest {
         assertEquals(20, result.get(0).getAge());
         assertEquals(1, result.size());
     }
+
+    @Test
+    public void testNamedQuery() {
+        Member m1 = new Member("aaa", 10);
+        Member m2 = new Member("bbb", 20);
+        memberJpaRepository.save(m1);
+        memberJpaRepository.save(m2);
+
+        List<Member> result = memberJpaRepository.findByUsername("aaa");
+
+        assertEquals(m1, result.get(0));
+    }
 }

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

@@ -72,4 +72,16 @@ public class MemberRepositoryTest {
         assertEquals(20, result.get(0).getAge());
         assertEquals(1, result.size());
     }
+
+    @Test
+    public void testNamedQuery() {
+        Member m1 = new Member("aaa", 10);
+        Member m2 = new Member("bbb", 20);
+        memberRepository.save(m1);
+        memberRepository.save(m2);
+
+        List<Member> result = memberRepository.findByUsername("aaa");
+
+        assertEquals(m1, result.get(0));
+    }
 }