[렉스] 2단계: 연관 관계 매핑

src/main/java/qna/Application.java

@@ -2,7 +2,9 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
 
+@EnableJpaAuditing
 @SpringBootApplication
 public class Application {
 

src/main/java/qna/domain/Answer.java

@@ -6,7 +6,9 @@
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.persistence.JoinColumn;
 import javax.persistence.Lob;
+import javax.persistence.ManyToOne;
 
 import qna.NotFoundException;
 import qna.UnAuthorizedException;
@@ -18,9 +20,13 @@ public class Answer extends BaseEntity {
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
-    private Long writerId;
+    @ManyToOne
+    @JoinColumn(name = "writer_id")
+    private User writer;
 
-    private Long questionId;
+    @ManyToOne
+    @JoinColumn(name = "question_id")
+    private Question question;
 
     @Lob
     private String contents;
@@ -45,17 +51,17 @@ public Answer(Long id, User writer, Question question, String contents) {
             throw new NotFoundException();
         }
 
-        this.writerId = writer.getId();
-        this.questionId = question.getId();
+        this.writer = writer;
+        this.question = question;
         this.contents = contents;
     }
 
     public boolean isOwner(User writer) {
-        return this.writerId.equals(writer.getId());
+        return this.writer.equals(writer);
     }
 
     public void toQuestion(Question question) {
-        this.questionId = question.getId();
+        this.question = question;
     }
 
     public Long getId() {
@@ -66,20 +72,20 @@ public void setId(Long id) {
         this.id = id;
     }
 
-    public Long getWriterId() {
-        return writerId;
+    public User getWriter() {
+        return writer;
     }
 
-    public void setWriterId(Long writerId) {
-        this.writerId = writerId;
+    public void setWriter(User writer) {
+        this.writer = writer;
     }
 
-    public Long getQuestion() {
-        return questionId;
+    public Question getQuestion() {
+        return question;
     }
 
     public void setQuestionId(Question question) {
-        this.questionId = question.getId();
+        this.question = question;
     }
 
     public String getContents() {
@@ -102,8 +108,8 @@ public void setDeleted(boolean deleted) {
     public String toString() {
         return "Answer{" +
                 "id=" + id +
-                ", writerId=" + writerId +
-                ", questionId=" + questionId +
+                ", writer=" + writer +
+                ", question=" + question +
                 ", contents='" + contents + '\'' +
                 ", deleted=" + deleted +
                 '}';

src/main/java/qna/domain/AnswerRepository.java

@@ -7,7 +7,7 @@
 
 public interface AnswerRepository extends JpaRepository<Answer, Long> {
 
-    List<Answer> findByQuestionIdAndDeletedFalse(Long questionId);
+    List<Answer> findByQuestionAndDeletedFalse(Long questionId);
 
     Optional<Answer> findByIdAndDeletedFalse(Long id);
 }

src/main/java/qna/domain/BaseEntity.java

@@ -3,19 +3,20 @@
 import java.time.LocalDateTime;
 
 import javax.persistence.Column;
+import javax.persistence.EntityListeners;
 import javax.persistence.MappedSuperclass;
 
-import org.hibernate.annotations.CreationTimestamp;
-import org.springframework.format.annotation.DateTimeFormat;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.jpa.domain.support.AuditingEntityListener;
 
+@EntityListeners(AuditingEntityListener.class)
 @MappedSuperclass
 public class BaseEntity {
 
-    @CreationTimestamp
+    @CreatedDate
     @Column(nullable = false)
     private LocalDateTime createdAt;
 
-    @DateTimeFormat
     private LocalDateTime updatedAt;
 
     public LocalDateTime getCreatedAt() {
@@ -25,4 +26,8 @@ public LocalDateTime getCreatedAt() {
     public LocalDateTime getUpdatedAt() {
         return updatedAt;
     }
+
+    public void updateTimeOfUpdated() {
+        this.updatedAt = LocalDateTime.now();
+    }
 }

src/main/java/qna/domain/DeleteHistory.java

@@ -4,14 +4,20 @@
 import java.util.Objects;
 
 import javax.persistence.Entity;
+import javax.persistence.EntityListeners;
 import javax.persistence.EnumType;
 import javax.persistence.Enumerated;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
 
 import org.hibernate.annotations.CreationTimestamp;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.jpa.domain.support.AuditingEntityListener;
 
+@EntityListeners(AuditingEntityListener.class)
 @Entity
 public class DeleteHistory {
 
@@ -21,19 +27,23 @@ public class DeleteHistory {
 
     @Enumerated(value = EnumType.STRING)
     private ContentType contentType;
+
     private Long contentId;
-    private Long deletedById;
 
-    @CreationTimestamp
+    @ManyToOne
+    @JoinColumn(name = "deleted_by_id")
+    private User deletedBy;
+
+    @CreatedDate
     private LocalDateTime createDate;
 
     protected DeleteHistory() {
     }
 
-    public DeleteHistory(ContentType contentType, Long contentId, Long deletedById) {
+    public DeleteHistory(ContentType contentType, Long contentId, User deletedBy) {
         this.contentType = contentType;
         this.contentId = contentId;
-        this.deletedById = deletedById;
+        this.deletedBy = deletedBy;
     }
 
     public Long getId() {
@@ -48,8 +58,8 @@ public Long getContentId() {
         return contentId;
     }
 
-    public Long getDeletedById() {
-        return deletedById;
+    public User getDeletedBy() {
+        return deletedBy;
     }
 
     public LocalDateTime getCreateDate() {
@@ -68,12 +78,12 @@ public boolean equals(Object o) {
         return Objects.equals(id, that.id) &&
                 contentType == that.contentType &&
                 Objects.equals(contentId, that.contentId) &&
-                Objects.equals(deletedById, that.deletedById);
+                Objects.equals(deletedBy, that.deletedBy);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(id, contentType, contentId, deletedById);
+        return Objects.hash(id, contentType, contentId, deletedBy);
     }
 
     @Override
@@ -82,7 +92,7 @@ public String toString() {
                 "id=" + id +
                 ", contentType=" + contentType +
                 ", contentId=" + contentId +
-                ", deletedById=" + deletedById +
+                ", deletedBy=" + deletedBy +
                 ", createDate=" + createDate +
                 '}';
     }

src/main/java/qna/domain/Question.java

@@ -5,7 +5,9 @@
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
+import javax.persistence.JoinColumn;
 import javax.persistence.Lob;
+import javax.persistence.ManyToOne;
 
 @Entity
 public class Question extends BaseEntity {
@@ -20,30 +22,28 @@ public class Question extends BaseEntity {
     @Lob
     private String contents;
 
-    private Long writerId;
+    @ManyToOne
+    @JoinColumn(name = "writer_id")
+    private User writer;
 
     private boolean deleted;
 
     protected Question() {
     }
 
-    public Question(String title, String contents) {
-        this(null, title, contents);
+    public Question(String title, String contents, User writer) {
+        this(null, title, contents, writer);
     }
 
-    public Question(Long id, String title, String contents) {
+    public Question(Long id, String title, String contents, User writer) {
         this.id = id;
         this.title = title;
         this.contents = contents;
-    }
-
-    public Question writeBy(User writer) {
-        this.writerId = writer.getId();
-        return this;
+        this.writer = writer;
     }
 
     public boolean isOwner(User writer) {
-        return this.writerId.equals(writer.getId());
+        return this.writer.equals(writer);
     }
 
     public void addAnswer(Answer answer) {
@@ -74,12 +74,12 @@ public void setContents(String contents) {
         this.contents = contents;
     }
 
-    public Long getWriterId() {
-        return writerId;
+    public User getWriter() {
+        return writer;
     }
 
-    public void setWriterId(Long writerId) {
-        this.writerId = writerId;
+    public void setWriterId(User writer) {
+        this.writer = writer;
     }
 
     public boolean isDeleted() {
@@ -96,7 +96,7 @@ public String toString() {
                 "id=" + id +
                 ", title='" + title + '\'' +
                 ", contents='" + contents + '\'' +
-                ", writerId=" + writerId +
+                ", writer=" + writer +
                 ", deleted=" + deleted +
                 '}';
     }

src/main/java/qna/domain/User.java

@@ -30,7 +30,7 @@ public class User extends BaseEntity {
     @Column(length = 50)
     private String email;
 
-    public User() {
+    protected User() {
     }
 
     public User(String userId, String password, String name, String email) {

src/main/java/qna/service/QnaService.java

@@ -22,9 +22,9 @@
 public class QnaService {
     private static final Logger log = LoggerFactory.getLogger(QnaService.class);
 
-    private QuestionRepository questionRepository;
-    private AnswerRepository answerRepository;
-    private DeleteHistoryService deleteHistoryService;
+    private final QuestionRepository questionRepository;
+    private final AnswerRepository answerRepository;
+    private final DeleteHistoryService deleteHistoryService;
 
     public QnaService(QuestionRepository questionRepository, AnswerRepository answerRepository,
                       DeleteHistoryService deleteHistoryService) {
@@ -39,14 +39,23 @@ public Question findQuestionById(Long id) {
                 .orElseThrow(NotFoundException::new);
     }
 
+    @Transactional
+    public void updateQuestionContent(Long id, String contents) {
+        Question question = questionRepository.findByIdAndDeletedFalse(id)
+                .orElseThrow(NotFoundException::new);
+        question.setContents(contents);
+        question.updateTimeOfUpdated();
+    }
+
     @Transactional
     public void deleteQuestion(User loginUser, Long questionId) throws CannotDeleteException {
         Question question = findQuestionById(questionId);
         if (!question.isOwner(loginUser)) {
             throw new CannotDeleteException("질문을 삭제할 권한이 없습니다.");
         }
 
-        List<Answer> answers = answerRepository.findByQuestionIdAndDeletedFalse(questionId);
+        List<Answer> answers = answerRepository.findByQuestionAndDeletedFalse(questionId);
+
         for (Answer answer : answers) {
             if (!answer.isOwner(loginUser)) {
                 throw new CannotDeleteException("다른 사람이 쓴 답변이 있어 삭제할 수 없습니다.");
@@ -55,10 +64,10 @@ public void deleteQuestion(User loginUser, Long questionId) throws CannotDeleteE
 
         List<DeleteHistory> deleteHistories = new ArrayList<>();
         question.setDeleted(true);
-        deleteHistories.add(new DeleteHistory(ContentType.QUESTION, questionId, question.getWriterId()));
+        deleteHistories.add(new DeleteHistory(ContentType.QUESTION, questionId, question.getWriter()));
         for (Answer answer : answers) {
             answer.setDeleted(true);
-            deleteHistories.add(new DeleteHistory(ContentType.ANSWER, answer.getId(), answer.getWriterId()));
+            deleteHistories.add(new DeleteHistory(ContentType.ANSWER, answer.getId(), answer.getWriter()));
         }
         deleteHistoryService.saveAll(deleteHistories);
     }