# 강의 # 관련링크 - [리포지터리](https://github.com/sik2/chat-app-mession/tree/feature/%231) - [재생목록](https://www.youtube.com/playlist?list=PLMzNIYZSiq7ZZrICNt_-_DUA7qZ2aUf3N) # 강의 # 1강 - [25 1 8, p 13946, 1강, 기존 레포에서 프로젝트 셋팅](https://youtu.be/l43GFwcFCSk) - [GIT](https://github.com/sik2/chat-app-mession/commit/25fcc00) - 브랜치 feature/#1 ```bash git checkout -b feature/#1 ``` - `<프로젝트명>` 본인 프로젝트 명으로 변경 ```yml spring: logging: level: com.ll.`<프로젝트명>`: DEBUG org.hibernate.orm.jdbc.bind: TRACE org.hibernate.orm.jdbc.extract: TRACE org.springframework.transaction.interceptor: TRACE ``` # 2강 - [25 1 8, p 13946, 2강, RsData 변경](https://youtu.be/n270lSO7tCI) - [GIT](https://github.com/sik2/chat-app-mession/commit/b661a06) - RsData.java ```java import lombok.AllArgsConstructor; import lombok.Getter; import static lombok.AccessLevel.PROTECTED; @AllArgsConstructor(access = PROTECTED) @Getter public class RsData { private final String resultCode; private final String msg; private final T data; private final int statusCode; public static RsData of(String resultCode, String msg, T data) { int statusCode = Integer.parseInt(resultCode); return new RsData<>(resultCode, msg, data, statusCode); } public boolean isSuccess() { return statusCode >= 200 && statusCode < 400; } public boolean isFail() { return !isSuccess(); } } ``` # 3강 - [25 1 8, p 13946, 3강, 회원가입 서비스 테스트 코드](https://youtu.be/mkRHTZdxXpQ) - [GIT](https://github.com/sik2/chat-app-mession/commit/) - 테스트 코드 작성 ```java @SpringBootTest @ActiveProfiles("test") @Transactional public class MemberServiceTest { @Autowired private MemberService memberService; @DisplayName("회원가입") @Test void t1() { RsData joinRs = memberService.join("usernew", "1234"); Member member = joinRs.getData(); assertThat(member.getId()).isGreaterThan(0L); } } ``` # 4강 - [25 1 8, p 13946, 4강, 회원가입 서비스 구현](https://youtu.be/4nAJJyuMdac) - [GIT](https://github.com/sik2/chat-app-mession/commit/64d2a11) # 5강 - [25 1 8, p 13946, 5강, 회원 데이터 3개 생성](https://youtu.be/yKf7sRALYv8) - [GIT](https://github.com/sik2/chat-app-mession/commit/835d6df) - NotProd.java ```java Member member1 = memberService.join("user1", "1234").getData(); Member member2 = memberService.join("user2", "1234").getData(); Member member3 = memberService.join("user3", "1234").getData(); ``` # 6강 - [25 1 8, p 13946, 6강, 게시글 서비스 테스트 코드](https://youtu.be/zVSkbyg6Yns) - [GIT](https://github.com/sik2/chat-app-mession/commit/) - 테스트 코드 ```java @SpringBootTest @ActiveProfiles("test") @Transactional public class ArticleServiceTest { @Autowired private ArticleService articleService; @DisplayName("글 쓰기") @Test void t1() { RsData

writeRs = articleService.write(1, "제목", "내용"); Article article = writeRs.getData(); assertThat(article.getId()).isGreaterThan(0L); } } ``` # 7강 - [25 1 8, p 13946, 7강, 게시글 생성 서비스 구현](https://youtu.be/ismw7Gsk3JY) - [GIT](https://github.com/sik2/chat-app-mession/commit/46e32db) - 게시글 생성 ```java public RsData

write(long authorId, String title, String body) { Article article = Article.builder() .modifyDate(LocalDateTime.now()) .author(Member.builder().id(authorId).build()) .title(title) .body(body) .build(); articleRepository.save(article); return RsData.of("200", "%d번 게시글이 작성되었습니다.".formatted(article.getId()), article); } ``` # 8강 - [25 1 8, p 13946, 8강, 게시글 데이터 4개 생성](https://youtu.be/7wjHR0cc7Xo) - [GIT](https://github.com/sik2/chat-app-mession/commit/46e32db) - NotProd.java ```java Article article1 = articleService.write(member1.getId(), "제목1", "내용1").getData(); Article article2 = articleService.write(member1.getId(), "제목2", "내용2").getData(); Article article3 = articleService.write(member2.getId(), "제목3", "내용3").getData(); Article article4 = articleService.write(member2.getId(), "제목4", "내용4").getData(); ``` # 9강 - [25 1 2, p 13946, 9강, 게시글 조회](https://youtu.be/P3W1MLIV24c) - [GIT](https://github.com/sik2/chat-app-mession/commit/e97198f) - 테스트 코드 ```java @DisplayName("1번 글을 가져온다.") @Test void t2() { Article article = articleService.findById(1L).get(); assertThat(article.getTitle()).isEqualTo("제목1"); } @DisplayName("1번 글의 작성자의 username 은 user1 이다.") @Test void t3() { Article article = articleService.findById(1L).get(); Member author = article.getAuthor(); assertThat(author.getUsername()).isEqualTo("user1"); } ``` # 10강 - [25 1 8, p 13946, 10강, 게시글 수정](https://youtu.be/DlBE_7jL-Gk) - [GIT](https://github.com/sik2/chat-app-mession/commit/b6d9d77) - 테스트 코드 ```java @DisplayName("1번 글의 제목을 수정한다.") @Test void t4() { Article article = articleService.findById(1L).get(); articleService.modify(article, "수정된 제목", "수정된 내용"); Article article_ = articleService.findById(1L).get(); assertThat(article_.getTitle()).isEqualTo("수정된 제목"); } } ``` $$hide - // Ut.thread.sleep(1000); - Ut.java ```java public class Ut { public static class thread { @SneakyThrows public static void sleep(int milli) { Thread.sleep(milli); } } } ``` $$ # 11강 - [25 1 9, p 13946, 11강, 영속성 컨텍스트는 보이지 않는 곳에서 최적화](https://youtu.be/S1__iEmXbf0) ```java @ActiveProfiles({"test", "dev"}) public class ArticleServiceTest { @DisplayName("1번 글의 제목을 수정한다.") @Test void t4() { Article article = articleService.findById(1L).get(); System.out.println(article); // articleService.modify(article, "수정된 제목", "수정된 내용"); Article article_ = articleService.findById(1L).get(); System.out.println(article); // assertThat(article_.getTitle()).isEqualTo("수정된 제목"); } } ``` # 12강 - [25 1 9, p 13946, 12강, 영속성 컨텍스트 더티체킹](https://youtu.be/K9txZMRHR4c) - [GIT](https://github.com/sik2/chat-app-mession/commit/180d1de) # 댓글 # 13강 - [25 1 9, p 13946, 13강, 댓글 서비스 구현](https://youtu.be/gF9-LxMzDzU) - [GIT](https://github.com/sik2/chat-app-mession/commit/a3b6c86) - 테스트 코드 ```java @DisplayName("2번 글에 댓글들을 추가한다.") @Test @Rollback(false) void t5() { Member member1 = memberService.findById(1L).get(); Article article2 = articleService.findById(2L).get(); article2.addComment(member1, "댓글 입니다."); } ``` # 14강 - [25 1 9, p 13946, 14강, 댓글 데이터 생성](https://youtu.be/vM3rIi3pJWs) - [GIT v1](https://github.com/sik2/chat-app-mession/commit/9ede8bf) - [GIT v2](https://github.com/sik2/chat-app-mession/commit/401e90f) - NotProd.java ```java // ArticleRepository articleRepository 추가 article1.addComment(member1, "댓글1"); article1.addComment(member1, "댓글2"); article2.addComment(member1, "댓글3"); article2.addComment(member1, "댓글4"); article2.addComment(member1, "댓글5"); article3.addComment(member1, "댓글5"); article3.addComment(member1, "댓글6"); article3.addComment(member1, "댓글7"); article3.addComment(member1, "댓글8"); article3.addComment(member1, "댓글9"); article3.addComment(member1, "댓글10"); article3.addComment(member1, "댓글11"); article3.addComment(member1, "댓글12"); articleRepository.save(article1); articleRepository.save(article2); articleRepository.save(article3); ``` # 15강 - [25 1 9, p 13946, 15강, 댓글 수정, 삭제](https://youtu.be/44KBhxckf5Q) - [GIT](https://github.com/sik2/chat-app-mession/commit/0a460af) - 테스트 코드 ```java @DisplayName("1번 글의 댓글들을 수정한다.") @Test void t6() { Article article = articleService.findById(2L).get(); article.getComments().forEach(comment -> { articleService.modifyComment(comment, comment.getBody() + "!!"); }); } @DisplayName("1번 글의 댓글 중 마지막 것을 삭제한다.") @Test void t7() { Article article = articleService.findById(2L).get(); ArticleComment lastComment = article.getComments().getLast(); article.removeComment(lastComment); } ``` # 16강 - [25 1 9, p 13946, 16강, 게시물 별 댓글 수 출력, n + 1 문제](https://youtu.be/ZVxoxpgffKc) - [GIT](https://github.com/sik2/chat-app-mession/commit/2ecb37a) - 테스트 코드 ```java @DisplayName("게시물 별 댓글 수 출력") @Test void t8() { List

articles = articleService.findAll(); articles.forEach(article -> { System.out.println("게시물 번호: " + article.getId()); System.out.println("댓글 수: " + article.getComments().size()); }); } ``` # 17강 - [25 1 8, p 13946, 17강, 참조 데이터 삭제,default_batch_fetch_size 관련 몇가지 추가작업](https://youtu.be/Jj_ZWEr3YaY) - [GIT](https://github.com/sik2/chat-app-mession/commit/9303f22) # 태그 # 18강 - [25 1 9, p 13946, 18강, 태그 추가 구현](https://youtu.be/l0X77Zu92bg) - [GIT](https://github.com/sik2/chat-app-mession/commit/cd0bc0f) # 19강 - [25 1 8, p 13946, 19강, 댓글, 가변 파라미터](https://youtu.be/MLVmn3Nms5k) - [GIT](https://github.com/sik2/chat-app-mession/commit/441a2a4) - NotProd.java ```java article1.addTag("자바"); article1.addTag("백엔드"); article2.addTag("프레임워크", "스프링부트"); article4.addTag("자바", "스프링부트"); ``` # 20강 - [25 1 9, p 13946, 20강, 태그 조회 테스트](https://youtu.be/HrpKti8RlvU) - [GIT](https://github.com/sik2/chat-app-mession/commit/98308c6) - 테스트 코드 ```java @DisplayName("1번 게시물의 태그(String)를 반환한다.") @Test void t9() { Article article1 = articleService.findById(1L).get(); String tagsStr = article1.getTagsStr(); assertThat(tagsStr).isEqualTo("#자바 #백엔드"); } ``` ## JPA 양방향 관계기능이 없었다면 아래의 SQL 을 직접 작성했어야 합니다. # 1번 글의 태그를 하나의 문자열로 합치는 SQL ```sql SELECT CONCAT("#", GROUP_CONCAT(content SEPARATOR ' #')) FROM article_tag WHERE article_id = 1; ``` # 21강 - [25 1 9, p 13946, 21강, 무한순환 참조 해결](https://youtu.be/QTpjvTPleuk) - [GIT](https://github.com/sik2/chat-app-mession/commit/50be672) # 1번 게시물 toString ```java @DisplayName("1번 게시물 toString") @Test void t10() { Article article1 = articleService.findById(1L).get(); System.out.println(article1); } ``` - Article OneToMany 관계 때문에 @ToString.Exclude 로 해결 # 22강 - [25 1 9, p 13946, 22강, 1번 회원이 작성한 댓글들](https://youtu.be/q7TKXPmae_c) - [GIT](https://github.com/sik2/chat-app-mession/commit/69ac7a9) ```java @DisplayName("1번 회원이 작성한 댓글들") @Test void t11() { List articleComments = articleCommentService.findByAuthorId(1L); assertThat(articleComments.size()).isGreaterThan(0); } ``` ## 리포지터리 메서드 ```java public List findByAuthorId(long authorId) { return articleCommentRepository.findByArticle_authorId(authorId); } ``` ## 실제로 실행되는 SQL ```sql SELECT AC.* FROM article_comment AS AC WHERE AC.author_id = 1; ``` # 23강 - [25 1 9, p 13946, 23강, 1번 회원이 작성한 태그들](https://youtu.be/YcrwaWRqNbE) - [GIT](https://github.com/sik2/chat-app-mession/commit/cac31dd) ```java @DisplayName("1번 회원이 작성한 태그들") @Test void t12() { List articleTags = articleTagService.findByAuthorId(1L); assertThat(articleTags.size()).isGreaterThan(0); } ``` ## 리포지터리 메서드 ```java public List findByAuthorId(long authorId) { return articleTagRepository.findByArticle_authorId(authorId); } ``` ## 실제로 실행되는 SQL ```sql SELECT ATG.* FROM article_tag AS ATG LEFT JOIN article AS A ON ATG.article_id = A.id WHERE A.author_id = 1; ``` # 24강 - [25 1 9, p 13946, 24강, 아이디가 user1 인 회원이 작성한 태그들](https://youtu.be/LcmY1QMG8-U) - [GIT](https://github.com/sik2/chat-app-mession/commit/cac31dd) ```java @DisplayName("아이디가 user1 인 회원이 작성한 태그들") @Test void t13() { List articleTags = articleTagService.findByAuthorUsername("user1"); assertThat(articleTags.size()).isGreaterThan(0); } ``` ## 리포지터리 메서드 ```java public List findByAuthorUsername(String username) { return articleTagRepository.findByArticle_author_username(username); } ``` ## 실제로 실행되는 SQL ```sql SELECT ATG.* FROM article_tag AS ATG LEFT JOIN article AS A ON ATG.article_id = A.id LEFT JOIN `member` AS M ON A.author_id = M.id WHERE M.username = 'user1'; ``` # 25강 - [25 1 9, p 13946, 25강, 영속성 컨텍스트, 동등성 비교 베이스 엔티티 설정](https://youtu.be/_ahIYUlR39I) ```java (...) @EqualsAndHashCode(onlyExplicitlyIncluded = true) (...) public class BaseEntity { (...) @EqualsAndHashCode.Include private Long id; (...) } ``` # 26강 ## 총정리 - [25 1 9, p 13946, 26강, 지금까지 학습한 내용 정리](https://youtu.be/rB6SjBXbcpk) - @Transactional 어노테이션 사용 - Service 클래스에 @Transactional(readOnly = true) 사용 - 메서드 단에서는 생성, 수정, 삭제에 @Transactional 어노테이션 사용 - 영속성 컨텍스트 - 중복작업 효율적으로 처리 - 더티체킹으로 수정 삭제 가능 - N + 1 문제 - @OneToMany 어노테이션 사용 - default_batch_fetch_size 100 옵션 추가 - @ManyToOne(fetch = FetchType.LAZY) 어노테이션 사용 - 영속성 컨텍스트, 동등성 비교 베이스 엔티티 설정 ```java (...) @EqualsAndHashCode(onlyExplicitlyIncluded = true) (...) public class BaseEntity { (...) @EqualsAndHashCode.Include private Long id; (...) } ```