feat: comment 도메인 및 기능 구현

src/main/java/org/sopt/article/entity/Article.java

@@ -4,9 +4,12 @@
 import lombok.*;
 import org.hibernate.annotations.BatchSize;
 import org.sopt.article.exception.ArticleException;
+import org.sopt.comment.entity.Comment;
 import org.sopt.member.entity.Member;
 import org.sopt.util.entity.BaseEntity;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Objects;
 
 import static org.sopt.article.exception.ArticleErrorCode.*;
@@ -34,6 +37,10 @@ public class Article extends BaseEntity {
     @Enumerated(EnumType.STRING)
     private ArticleTag tag;
 
+    @Builder.Default
+    @OneToMany(mappedBy = "article", cascade = CascadeType.REMOVE, orphanRemoval = true)
+    private List<Comment> comments = new ArrayList<>();
+
     public static Article create(Member member, String title, String content, ArticleTag tag) {
         validateMember(member);
         validateTitle(title);

src/main/java/org/sopt/comment/controller/CommentController.java

@@ -0,0 +1,73 @@
+package org.sopt.comment.controller;
+
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.sopt.comment.controller.spec.CommentControllerDocs;
+import org.sopt.comment.dto.request.CommentCreateRequest;
+import org.sopt.comment.dto.request.CommentUpdateRequest;
+import org.sopt.comment.dto.response.CommentResponse;
+import org.sopt.comment.service.CommentService;
+import org.sopt.util.BaseResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/articles/{articleId}/comments")
+@RequiredArgsConstructor
+public class CommentController implements CommentControllerDocs {
+
+    private final CommentService commentService;
+
+    @Override
+    @PostMapping
+    public ResponseEntity<BaseResponse<Long>> createComment(
+            @PathVariable Long articleId,
+            @Valid @RequestBody CommentCreateRequest request
+    ) {
+        return ResponseEntity
+                .status(HttpStatus.CREATED)
+                .body(BaseResponse.onCreated(commentService.createComment(articleId, request)));
+    }
+
+    @Override
+    @GetMapping
+    public ResponseEntity<BaseResponse<List<CommentResponse>>> getCommentsByArticle(
+            @PathVariable Long articleId
+    ) {
+        return ResponseEntity.ok(BaseResponse.onSuccess(commentService.findCommentsByArticleId(articleId)));
+    }
+
+    @Override
+    @GetMapping("/{commentId}")
+    public ResponseEntity<BaseResponse<CommentResponse>> getCommentById(
+            @PathVariable Long articleId,
+            @PathVariable Long commentId
+    ) {
+        return ResponseEntity.ok(BaseResponse.onSuccess(commentService.findCommentById(articleId, commentId)));
+    }
+
+    @Override
+    @PutMapping("/{commentId}")
+    public ResponseEntity<BaseResponse<Void>> updateComment(
+            @PathVariable Long articleId,
+            @PathVariable Long commentId,
+            @Valid @RequestBody CommentUpdateRequest request
+    ) {
+        commentService.updateComment(articleId, commentId, request);
+        return ResponseEntity.ok(BaseResponse.onSuccess());
+    }
+
+    @Override
+    @DeleteMapping("/{commentId}")
+    public ResponseEntity<BaseResponse<Void>> deleteComment(
+            @PathVariable Long articleId,
+            @PathVariable Long commentId,
+            @RequestParam Long memberId
+    ) {
+        commentService.deleteComment(articleId, commentId, memberId);
+        return ResponseEntity.ok(BaseResponse.onSuccess());
+    }
+}

src/main/java/org/sopt/comment/controller/spec/CommentControllerDocs.java

@@ -0,0 +1,78 @@
+package org.sopt.comment.controller.spec;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import org.sopt.comment.dto.request.CommentCreateRequest;
+import org.sopt.comment.dto.request.CommentUpdateRequest;
+import org.sopt.comment.dto.response.CommentResponse;
+import org.sopt.util.BaseResponse;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestParam;
+
+import java.util.List;
+
+@Tag(name = "Comment", description = "댓글 관리 API")
+public interface CommentControllerDocs {
+
+    @Operation(summary = "댓글 생성", description = "게시글에 새로운 댓글을 작성합니다.")
+    @ApiResponses({
+            @ApiResponse(responseCode = "201", description = "댓글 생성 성공"),
+            @ApiResponse(responseCode = "400", description = "잘못된 요청", content = @Content),
+            @ApiResponse(responseCode = "404", description = "게시글 또는 작성자를 찾을 수 없음", content = @Content)
+    })
+    ResponseEntity<BaseResponse<Long>> createComment(
+            @Parameter(description = "게시글 ID", required = true) @PathVariable Long articleId,
+            @Valid @RequestBody CommentCreateRequest request
+    );
+
+    @Operation(summary = "댓글 목록 조회", description = "게시글의 모든 댓글을 조회합니다.")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "조회 성공"),
+            @ApiResponse(responseCode = "404", description = "게시글을 찾을 수 없음", content = @Content)
+    })
+    ResponseEntity<BaseResponse<List<CommentResponse>>> getCommentsByArticle(
+            @Parameter(description = "게시글 ID", required = true) @PathVariable Long articleId
+    );
+
+    @Operation(summary = "댓글 상세 조회", description = "특정 댓글을 조회합니다.")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "조회 성공"),
+            @ApiResponse(responseCode = "404", description = "게시글 또는 댓글을 찾을 수 없음", content = @Content)
+    })
+    ResponseEntity<BaseResponse<CommentResponse>> getCommentById(
+            @Parameter(description = "게시글 ID", required = true) @PathVariable Long articleId,
+            @Parameter(description = "댓글 ID", required = true) @PathVariable Long commentId
+    );
+
+    @Operation(summary = "댓글 수정", description = "댓글 내용을 수정합니다.")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "수정 성공"),
+            @ApiResponse(responseCode = "400", description = "잘못된 요청", content = @Content),
+            @ApiResponse(responseCode = "403", description = "수정 권한 없음", content = @Content),
+            @ApiResponse(responseCode = "404", description = "게시글 또는 댓글을 찾을 수 없음", content = @Content)
+    })
+    ResponseEntity<BaseResponse<Void>> updateComment(
+            @Parameter(description = "게시글 ID", required = true) @PathVariable Long articleId,
+            @Parameter(description = "댓글 ID", required = true) @PathVariable Long commentId,
+            @Valid @RequestBody CommentUpdateRequest request
+    );
+
+    @Operation(summary = "댓글 삭제", description = "댓글을 삭제합니다.")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "삭제 성공"),
+            @ApiResponse(responseCode = "403", description = "삭제 권한 없음", content = @Content),
+            @ApiResponse(responseCode = "404", description = "게시글 또는 댓글을 찾을 수 없음", content = @Content)
+    })
+    ResponseEntity<BaseResponse<Void>> deleteComment(
+            @Parameter(description = "게시글 ID", required = true) @PathVariable Long articleId,
+            @Parameter(description = "댓글 ID", required = true) @PathVariable Long commentId,
+            @Parameter(description = "작성자 ID", required = true) @RequestParam Long memberId
+    );
+}

src/main/java/org/sopt/comment/dto/request/CommentCreateRequest.java

@@ -0,0 +1,15 @@
+package org.sopt.comment.dto.request;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+
+public record CommentCreateRequest(
+        @NotNull(message = "작성자 ID는 필수 입력 항목입니다.")
+        Long memberId,
+
+        @NotBlank(message = "댓글 내용은 필수 입력 항목입니다.")
+        @Size(min = 1, max = 1000, message = "댓글은 최소 1자 이상, 최대 1000자까지 입력 가능합니다.")
+        String content
+) {
+}

src/main/java/org/sopt/comment/dto/request/CommentUpdateRequest.java

@@ -0,0 +1,15 @@
+package org.sopt.comment.dto.request;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+
+public record CommentUpdateRequest(
+        @NotNull(message = "작성자 ID는 필수 입력 항목입니다.")
+        Long memberId,
+
+        @NotBlank(message = "댓글 내용은 필수 입력 항목입니다.")
+        @Size(min = 1, max = 1000, message = "댓글은 최소 1자 이상, 최대 1000자까지 입력 가능합니다.")
+        String content
+) {
+}

src/main/java/org/sopt/comment/dto/response/CommentResponse.java

@@ -0,0 +1,23 @@
+package org.sopt.comment.dto.response;
+
+import org.sopt.comment.entity.Comment;
+
+import java.time.LocalDateTime;
+
+public record CommentResponse(
+        Long id,
+        String content,
+        String authorName,
+        LocalDateTime createdAt,
+        LocalDateTime updatedAt
+) {
+    public static CommentResponse from(Comment comment) {
+        return new CommentResponse(
+                comment.getId(),
+                comment.getContent(),
+                comment.getMember().getName(),
+                comment.getCreatedAt(),
+                comment.getUpdatedAt()
+        );
+    }
+}

src/main/java/org/sopt/comment/entity/Comment.java

@@ -0,0 +1,103 @@
+package org.sopt.comment.entity;
+
+import jakarta.persistence.*;
+import lombok.*;
+import org.sopt.article.entity.Article;
+import org.sopt.comment.exception.CommentException;
+import org.sopt.member.entity.Member;
+import org.sopt.util.entity.BaseEntity;
+
+import java.util.Objects;
+
+import static org.sopt.comment.exception.CommentErrorCode.*;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@Builder
+public class Comment extends BaseEntity {
+
+    private static final int MAX_CONTENT_LENGTH = 300;
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "article_id", nullable = false)
+    private Article article;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "member_id", nullable = false)
+    private Member member;
+
+    @Column(nullable = false, length = MAX_CONTENT_LENGTH)
+    private String content;
+
+    public static Comment create(Article article, Member member, String content) {
+        validateArticle(article);
+        validateMember(member);
+        validateContent(content);
+
+        return Comment.builder()
+                .article(article)
+                .member(member)
+                .content(content)
+                .build();
+    }
+
+    public void updateContent(String content) {
+        validateContent(content);
+        this.content = content;
+    }
+
+    public void validateOwnership(Long memberId) {
+        if (!this.member.getId().equals(memberId)) {
+            throw new CommentException(COMMENT_UNAUTHORIZED);
+        }
+    }
+
+    public void validateBelongsToArticle(Long articleId) {
+        if (!this.article.getId().equals(articleId)) {
+            throw new CommentException(COMMENT_ARTICLE_MISMATCH);
+        }
+    }
+
+    private static void validateArticle(Article article) {
+        if (article == null) {
+            throw new CommentException(COMMENT_ARTICLE_REQUIRED);
+        }
+    }
+
+    private static void validateMember(Member member) {
+        if (member == null) {
+            throw new CommentException(COMMENT_MEMBER_REQUIRED);
+        }
+    }
+
+    private static void validateContent(String content) {
+        if (content == null || content.trim().isEmpty()) {
+            throw new CommentException(COMMENT_CONTENT_REQUIRED);
+        }
+        if (content.length() > MAX_CONTENT_LENGTH) {
+            throw new CommentException(COMMENT_CONTENT_TOO_LONG);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof Comment comment)) {
+            return false;
+        }
+        return this.id != null && this.id.equals(comment.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.id);
+    }
+}

src/main/java/org/sopt/comment/exception/CommentErrorCode.java

@@ -0,0 +1,48 @@
+package org.sopt.comment.exception;
+
+import org.sopt.util.exception.ErrorCode;
+import org.springframework.http.HttpStatus;
+
+public enum CommentErrorCode implements ErrorCode {
+
+    COMMENT_NOT_FOUND(HttpStatus.NOT_FOUND, "COMMENT_NOT_FOUND", "해당 ID의 댓글을 찾을 수 없습니다."),
+    COMMENT_ARTICLE_NOT_FOUND(HttpStatus.NOT_FOUND, "COMMENT_ARTICLE_NOT_FOUND", "댓글을 작성할 게시글을 찾을 수 없습니다."),
+    COMMENT_MEMBER_NOT_FOUND(HttpStatus.NOT_FOUND, "COMMENT_MEMBER_NOT_FOUND", "댓글 작성자를 찾을 수 없습니다."),
+    COMMENT_UNAUTHORIZED(HttpStatus.FORBIDDEN, "COMMENT_UNAUTHORIZED", "댓글을 수정/삭제할 권한이 없습니다."),
+    COMMENT_ARTICLE_MISMATCH(HttpStatus.BAD_REQUEST, "COMMENT_ARTICLE_MISMATCH", "해당 게시글의 댓글이 아닙니다."),
+
+    COMMENT_ARTICLE_REQUIRED(HttpStatus.BAD_REQUEST, "COMMENT_ARTICLE_REQUIRED", "게시글은 필수 입력 항목입니다."),
+    COMMENT_MEMBER_REQUIRED(HttpStatus.BAD_REQUEST, "COMMENT_MEMBER_REQUIRED", "작성자는 필수 입력 항목입니다."),
+    COMMENT_CONTENT_REQUIRED(HttpStatus.BAD_REQUEST, "COMMENT_CONTENT_REQUIRED", "댓글 내용은 필수 입력 항목입니다."),
+    COMMENT_CONTENT_TOO_LONG(HttpStatus.BAD_REQUEST, "COMMENT_CONTENT_TOO_LONG", "댓글은 최대 1000자까지 입력 가능합니다.");
+
+    private final HttpStatus httpStatus;
+    private final String code;
+    private final String message;
+
+    CommentErrorCode(HttpStatus httpStatus, String code, String message) {
+        this.httpStatus = httpStatus;
+        this.code = code;
+        this.message = message;
+    }
+
+    @Override
+    public HttpStatus getHttpStatus() {
+        return httpStatus;
+    }
+
+    @Override
+    public String getCode() {
+        return code;
+    }
+
+    @Override
+    public String getMessage() {
+        return message;
+    }
+
+    @Override
+    public String format(Object... args) {
+        return String.format(message, args);
+    }
+}