3-2

.gitignore

@@ -35,3 +35,6 @@ out/
 
 ### VS Code ###
 .vscode/
+
+# .gitignore 파일에 추가
+application.yml

src/main/java/com/example/springhw32/controller/CommentController.java

@@ -1,5 +1,28 @@
 package com.example.springhw32.controller;
 
+import com.example.springhw32.dto.CommentDto;
+import com.example.springhw32.service.CommentService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/posts/comments")
+@RequiredArgsConstructor
 public class CommentController {
 
+    private final CommentService commentService;
+
+    // 댓글 작성
+    @PostMapping("/{postId}")
+    public CommentDto createComment(@RequestBody CommentDto commentDto, @PathVariable Long postId) {
+        return commentService.createComment(commentDto, postId);
+    }
+
+    // 특정 게시물에 달린 모든 댓글 조회
+    @GetMapping("/{postId}")
+    public List<CommentDto> getAllCommentsByPostId(@PathVariable Long postId) {
+        return commentService.getAllCommentsByPostId(postId);
+    }
 }

src/main/java/com/example/springhw32/controller/PostController.java

@@ -1,5 +1,39 @@
 package com.example.springhw32.controller;
 
+import com.example.springhw32.dto.PostDto;
+import com.example.springhw32.service.PostService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/posts")
+@RequiredArgsConstructor
 public class PostController {
 
+    private final PostService postService;
+
+    // 글 작성
+    @PostMapping
+    public PostDto createPost(@RequestBody PostDto postDto, @RequestParam String writer) {
+        return postService.createPost(postDto, writer);
+    }
+    // 최신순 글 조회
+    @GetMapping
+    public List<PostDto> getPostsSortedByDate() {
+        return postService.getPostsSortedByDate();
+    }
+
+    // 작성자 글 조회
+    @GetMapping("/{writer}")
+    public List<PostDto> getPostsByWriter(@PathVariable String writer) {
+        return postService.getPostsByWriter(writer);
+    }
+
+    // 댓글 많은 순 글 조회
+    @GetMapping("/comments")
+    public List<PostDto> getPostsSortedByComments() {
+        return postService.getPostsSortedByComments();
+    }
 }

src/main/java/com/example/springhw32/controller/UserController.java

@@ -1,5 +1,27 @@
 package com.example.springhw32.controller;
 
+import com.example.springhw32.dto.UserDto;
+import com.example.springhw32.service.UserService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/users")
 public class UserController {
 
-}
+    private final UserService userService;
+
+    @PostMapping
+    public UserDto join(@ModelAttribute UserDto userDto) {
+        return userService.join(userDto);
+    }
+
+    @PostMapping("/login")
+    public String login(@ModelAttribute UserDto userDto) {
+        return userService.login(userDto);
+    }
+}

src/main/java/com/example/springhw32/dto/CommentDto.java

@@ -1,5 +1,16 @@
 package com.example.springhw32.dto;
 
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
 public class CommentDto {
+    private Long commentId;
+
+    private Long postId;
+
+    private Long userId;
 
+    private String content;
 }

src/main/java/com/example/springhw32/dto/PostDto.java

@@ -1,5 +1,24 @@
 package com.example.springhw32.dto;
 
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
 public class PostDto {
+    private Long postId;
+
+    private String title;
+
+    private String content;
+
+    private String writer;
+
+    private Long commentCount;
+
+    private LocalDateTime createdAt;
 
+    private LocalDateTime updatedAt;
 }

src/main/java/com/example/springhw32/dto/UserDto.java

@@ -1,5 +1,19 @@
 package com.example.springhw32.dto;
 
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
 public class UserDto {
+    private Long userId;
+
+    private String username;
+
+    private String password;
+
+    private String nickname;
 
-}
+}

src/main/java/com/example/springhw32/entity/Comment.java

@@ -1,5 +1,25 @@
 package com.example.springhw32.entity;
 
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Getter
+@Setter
 public class Comment {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long commentId;
+
+    @Column(nullable = false)
+    private String content;
+
+    @ManyToOne
+    @JoinColumn(name = "userId", nullable = false)
+    private User user;
+
+    @ManyToOne
+    private Post post;
 }

src/main/java/com/example/springhw32/entity/Post.java

@@ -1,5 +1,32 @@
 package com.example.springhw32.entity;
 
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
+@Entity
 public class Post {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long postId;
+
+    @ManyToOne
+    private User user;
+
+    @Column(nullable = false)
+    private String title;
+
+    @Column(nullable = false)
+    private String content;
+
+    private Long commentCount = 0L;
+
+    private LocalDateTime createdAt;
+
+    private LocalDateTime updatedAt;
 }

src/main/java/com/example/springhw32/entity/User.java

@@ -1,5 +1,25 @@
 package com.example.springhw32.entity;
 
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
+@Entity
+@Getter
+@Setter
 public class User {
 
-}
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String username;
+
+    @Column(nullable = false)
+    private String password;
+
+    @Column(nullable = false, unique = true)
+    private String nickname;
+
+}

src/main/java/com/example/springhw32/repository/CommentRepository.java

@@ -1,5 +1,12 @@
 package com.example.springhw32.repository;
 
-public interface CommentRepository {
+import com.example.springhw32.entity.Comment;
+import com.example.springhw32.entity.User;
+import org.springframework.data.jpa.repository.JpaRepository;
 
-}
+import java.util.List;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+    // 특정 게시물에 달린 모든 댓글 조회
+    List<Comment> findByPost_PostId(Long postId);
+}

src/main/java/com/example/springhw32/repository/PostRepository.java

@@ -1,5 +1,13 @@
 package com.example.springhw32.repository;
 
-public interface PostRepository {
+import com.example.springhw32.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
 
+import java.util.List;
+
+public interface PostRepository extends JpaRepository<Post, Long> {
+    List<Post> findByUser_Nickname(String nickname);
+    List<Post> findAllByOrderByCreatedAtDesc();
+    List<Post> findAllByOrderByCommentCountDesc();
 }
+

src/main/java/com/example/springhw32/repository/UserRepository.java

@@ -1,5 +1,18 @@
 package com.example.springhw32.repository;
 
-public interface UserRepository {
+import com.example.springhw32.entity.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
 
+import java.util.Optional;
+
+@Repository
+public interface UserRepository extends JpaRepository<User, Long> {
+    User findByUsername(String username);
+
+    boolean existsByUsername(String username);
+
+    boolean existsByNickname(String nickname);
+
+    Optional<User> findByNickname(String nickname);
 }

src/main/java/com/example/springhw32/service/CommentService.java

@@ -1,5 +1,61 @@
 package com.example.springhw32.service;
 
+import com.example.springhw32.dto.CommentDto;
+import com.example.springhw32.entity.Comment;
+import com.example.springhw32.entity.Post;
+import com.example.springhw32.entity.User;
+import com.example.springhw32.repository.CommentRepository;
+import com.example.springhw32.repository.PostRepository;
+import com.example.springhw32.repository.UserRepository;
+import jakarta.transaction.Transactional;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.stream.Collectors;
+
+@Service
+@RequiredArgsConstructor
 public class CommentService {
 
+    private final CommentRepository commentRepository;
+    private final PostRepository postRepository;
+    private final UserRepository userRepository;
+
+    @Transactional
+    public CommentDto createComment(CommentDto commentDto, Long postId) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new NoSuchElementException("Post not found"));
+
+        User user = userRepository.findById(commentDto.getUserId())
+                .orElseThrow(() -> new NoSuchElementException("User not found"));
+
+        Comment comment = new Comment();
+        comment.setContent(commentDto.getContent());
+        comment.setUser(user);
+        comment.setPost(post);
+        commentRepository.save(comment);
+        post.setCommentCount(post.getCommentCount() + 1L);
+        postRepository.save(post);
+        return mapToDto(comment);
+    }
+
+
+    // 특정 게시물에 달린 모든 댓글 조회
+    public List<CommentDto> getAllCommentsByPostId(Long postId) {
+        return commentRepository.findByPost_PostId(postId).stream()
+                .map(this::mapToDto)
+                .collect(Collectors.toList());
+    }
+
+    // Comment -> CommentDto 변환
+    private CommentDto mapToDto(Comment comment) {
+        CommentDto dto = new CommentDto();
+        dto.setCommentId(comment.getCommentId());
+        dto.setPostId(comment.getPost().getPostId());
+        dto.setUserId(comment.getUser().getId());
+        dto.setContent(comment.getContent());
+        return dto;
+    }
 }