QueryDSL 섹션 1

Author: K-jun98

querydsl/build.gradle

@@ -28,6 +28,10 @@ dependencies {
     runtimeOnly 'com.h2database:h2'
     annotationProcessor 'org.projectlombok:lombok'
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    implementation 'com.querydsl:querydsl-jpa:5.0.0:jakarta'
+    annotationProcessor "com.querydsl:querydsl-apt:5.0.0:jakarta"
+    annotationProcessor "jakarta.annotation:jakarta.annotation-api"
+    annotationProcessor "jakarta.persistence:jakarta.persistence-api"
 }
 
 tasks.named('test') {

querydsl/src/main/java/dev/querydsl/entity/Hello.java

@@ -0,0 +1,15 @@
+package dev.querydsl.entity;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Getter
+@Setter
+public class Hello {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+}

querydsl/src/main/java/dev/querydsl/entity/Member.java

@@ -0,0 +1,42 @@
+package dev.querydsl.entity;
+
+import jakarta.persistence.*;
+import lombok.*;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@ToString(of = {"id", "username", "age"})
+public class Member {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @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);
+    }
+}

querydsl/src/main/java/dev/querydsl/entity/Team.java

@@ -0,0 +1,28 @@
+package dev.querydsl.entity;
+
+import jakarta.persistence.*;
+import lombok.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@ToString(of = {"id", "name"})
+public class Team {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "team_id")
+    private Long id;
+
+    private String name;
+
+    @OneToMany(mappedBy = "team")
+    private List<Member> members = new ArrayList<>();
+
+    public Team(String name) {
+        this.name = name;
+    }
+}

querydsl/src/main/resources/application.properties

@@ -0,0 +1,18 @@
+
+spring:
+  datasource:
+    url: jdbc:h2:tcp://localhost/~/test
+    username: sa
+    password:
+    driver-class-name: org.h2.Driver
+
+  jpa:
+    hibernate:
+      ddl-auto: create
+    properties:
+      hibernate:
+        format_sql: true
+    show_sql: true
+
+  logging.level:
+    org.hibernate.SQL: debug

querydsl/src/main/resources/application.yml

@@ -0,0 +1,66 @@
+package dev.querydsl;
+
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import dev.querydsl.entity.Member;
+import dev.querydsl.entity.QMember;
+import dev.querydsl.entity.Team;
+import jakarta.persistence.EntityManager;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.transaction.annotation.Transactional;
+
+@SpringBootTest
+@Transactional
+public class QuerydslBasicTest {
+
+    @Autowired
+    EntityManager em;
+
+    @BeforeEach
+    void before() {
+        Team teamA = new Team("teamA");
+        Team teamB = new Team("teamB");
+        em.persist(teamA);
+        em.persist(teamB);
+        Member member1 = new Member("member1", 10, teamA);
+        Member member2 = new Member("member2", 20, teamA);
+        Member member3 = new Member("member3", 30, teamB);
+        Member member4 = new Member("member4", 40, teamB);
+        em.persist(member1);
+        em.persist(member2);
+        em.persist(member3);
+        em.persist(member4);
+    }
+
+    @Test
+    void startJPQL() {
+        String qlString = """
+                select m from Member m
+                where m.username = :username
+                """;
+
+        Member findMember = em.createQuery(qlString, Member.class)
+                .setParameter("username", "member1")
+                .getSingleResult();
+
+        Assertions.assertThat(findMember.getUsername()).isEqualTo("member1");
+    }
+
+    @Test
+    void startQuerydsl() {
+
+        JPAQueryFactory queryFactory = new JPAQueryFactory(em);
+        QMember m = new QMember("m");
+
+        Member findMember = queryFactory
+                .select(m)
+                .from(m)
+                .where(m.username.eq("member1"))
+                .fetchOne();
+
+        Assertions.assertThat(findMember.getUsername()).isEqualTo("member1");
+    }
+}

querydsl/src/test/java/dev/querydsl/QuerydslBasicTest.java

@@ -0,0 +1,43 @@
+package dev.querydsl.entity;
+
+import jakarta.persistence.EntityManager;
+import jakarta.transaction.Transactional;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.annotation.Commit;
+
+import java.util.List;
+
+@SpringBootTest
+@Transactional
+class MemberTest {
+
+    @Autowired
+    EntityManager em;
+
+    @Test
+    public void testEntity() {
+        Team teamA = new Team("teamA");
+        Team teamB = new Team("teamB");
+        em.persist(teamA);
+        em.persist(teamB);
+        Member member1 = new Member("member1", 10, teamA);
+        Member member2 = new Member("member2", 20, teamA);
+        Member member3 = new Member("member3", 30, teamB);
+        Member member4 = new Member("member4", 40, teamB);
+        em.persist(member1);
+        em.persist(member2);
+        em.persist(member3);
+        em.persist(member4);
+em.flush();
+em.clear();
+        List<Member> members = em.createQuery("select m from Member m",
+                        Member.class)
+                .getResultList();
+        for (Member member : members) {
+            System.out.println("member=" + member);
+            System.out.println("-> member.team=" + member.getTeam());
+        }
+    }
+}