diff --git a/.gitignore b/.gitignore
index c2065bc..4c75e42 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,3 +35,5 @@ out/
 
 ### VS Code ###
 .vscode/
+
+.env
\ No newline at end of file
diff --git a/README.md b/README.md
index 395edc5..d8ca717 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,2 @@
 # backend-study-sns
+강지원
diff --git a/build.gradle b/build.gradle
index 610d6a6..cf03320 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,11 +19,27 @@ repositories {
 }
 
 dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 	implementation 'org.springframework.boot:spring-boot-starter-web'
-	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    implementation 'com.mysql:mysql-connector-j:9.0.0'
+    implementation 'me.paulschwarz:spring-dotenv:4.0.0'
+
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
 	testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+
+    // lombok
+    compileOnly 'org.projectlombok:lombok'
+    annotationProcessor 'org.projectlombok:lombok'
+    testCompileOnly 'org.projectlombok:lombok'
+    testAnnotationProcessor 'org.projectlombok:lombok'
 }
 
+configurations {
+    compileOnly {
+        extendsFrom annotationProcessor
+    }
+}
 tasks.named('test') {
 	useJUnitPlatform()
 }
diff --git a/src/main/java/com/example/devSns/controller/CommentController.java b/src/main/java/com/example/devSns/controller/CommentController.java
new file mode 100644
index 0000000..a040745
--- /dev/null
+++ b/src/main/java/com/example/devSns/controller/CommentController.java
@@ -0,0 +1,31 @@
+package com.example.devSns.controller;
+
+import com.example.devSns.entity.Comment;
+import com.example.devSns.service.CommentService;
+import org.springframework.web.bind.annotation.*;
+import java.util.List;
+
+@RestController
+@RequestMapping("post/{postId}/comment")
+public class CommentController {
+    private CommentService commentService;
+
+    public CommentController(CommentService commentService) {
+        this.commentService = commentService;
+    }
+
+    @GetMapping
+    public List<Comment> getComments(@PathVariable Long postId) {
+        return commentService.getCommentByPost(postId);
+    }
+
+    @PostMapping
+    public Comment createComment(@PathVariable Long postId, @RequestBody Comment comment) {
+        return commentService.addComment(postId, comment);
+    }
+
+    @DeleteMapping("/{commentId}")
+    public void deleteComment(@PathVariable Long commentId) {
+        commentService.deleteComment(commentId);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/controller/PostController.java b/src/main/java/com/example/devSns/controller/PostController.java
new file mode 100644
index 0000000..1a2a41f
--- /dev/null
+++ b/src/main/java/com/example/devSns/controller/PostController.java
@@ -0,0 +1,44 @@
+package com.example.devSns.controller;
+
+import com.example.devSns.entity.Post;
+import com.example.devSns.service.PostService;
+import org.springframework.web.bind.annotation.*;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@RestController
+@RequestMapping("/post")
+public class PostController {
+    private final PostService postService;
+
+    public PostController(PostService postService) {
+        this.postService = postService;
+    }
+
+    @GetMapping
+    public List<Post> getAllPosts(){
+        return postService.findAll();
+    }
+
+    @GetMapping("/{id}")
+    public Post getPostById(@PathVariable Long id){
+        return postService.findById(id).orElseThrow(()-> new RuntimeException("post not found"));
+    }
+
+    @PostMapping
+    public Post createPost(@RequestBody Post post){
+        return postService.save(post);
+    }
+
+    @PutMapping("/{id}")
+    public Post updatePost(@PathVariable Long id, @RequestBody Post updatedPost){
+
+        return postService.updatePost(id,updatedPost);
+    }
+
+    @DeleteMapping("/{id}")
+    public void deletePost(@PathVariable Long id){
+        postService.delete(id);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/entity/Comment.java b/src/main/java/com/example/devSns/entity/Comment.java
new file mode 100644
index 0000000..4eb30dc
--- /dev/null
+++ b/src/main/java/com/example/devSns/entity/Comment.java
@@ -0,0 +1,32 @@
+package com.example.devSns.entity;
+
+import com.fasterxml.jackson.annotation.JsonBackReference;
+import jakarta.persistence.*;
+import lombok.*;
+import java.time.LocalDateTime;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class Comment{
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String content;
+    private String username;
+    private LocalDateTime createdAt;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name="post_id")
+    @JsonBackReference
+    private Post post;
+
+    @PrePersist
+    public void onCreate(){
+        createdAt = LocalDateTime.now();
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/entity/Post.java b/src/main/java/com/example/devSns/entity/Post.java
new file mode 100644
index 0000000..143a980
--- /dev/null
+++ b/src/main/java/com/example/devSns/entity/Post.java
@@ -0,0 +1,41 @@
+package com.example.devSns.entity;
+
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+import jakarta.persistence.*;
+import lombok.*;
+
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class Post {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String content;
+    private int likes;
+    private String username;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
+
+    @OneToMany(mappedBy = "post", cascade = CascadeType.ALL,orphanRemoval = true)
+    @JsonManagedReference
+    private List<Comment> comments = new ArrayList<>();
+    @PrePersist
+    public void onCreate(){
+        createdAt = LocalDateTime.now();
+        updatedAt = LocalDateTime.now();
+    }
+
+    @PreUpdate
+    public void onUpdate(){
+        updatedAt = LocalDateTime.now();
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/repository/CommentRepository.java b/src/main/java/com/example/devSns/repository/CommentRepository.java
new file mode 100644
index 0000000..c293959
--- /dev/null
+++ b/src/main/java/com/example/devSns/repository/CommentRepository.java
@@ -0,0 +1,9 @@
+package com.example.devSns.repository;
+
+import com.example.devSns.entity.Comment;
+import org.springframework.data.jpa.repository.JpaRepository;
+import java.util.List;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+    List<Comment> findByPost_Id(Long postId);
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/repository/PostRepository.java b/src/main/java/com/example/devSns/repository/PostRepository.java
new file mode 100644
index 0000000..4fd8426
--- /dev/null
+++ b/src/main/java/com/example/devSns/repository/PostRepository.java
@@ -0,0 +1,6 @@
+package com.example.devSns.repository;
+
+import com.example.devSns.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PostRepository extends JpaRepository<Post, Long> {}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/service/CommentService.java b/src/main/java/com/example/devSns/service/CommentService.java
new file mode 100644
index 0000000..c2e8157
--- /dev/null
+++ b/src/main/java/com/example/devSns/service/CommentService.java
@@ -0,0 +1,33 @@
+package com.example.devSns.service;
+
+import com.example.devSns.entity.Comment;
+import com.example.devSns.entity.Post;
+import com.example.devSns.repository.CommentRepository;
+import com.example.devSns.repository.PostRepository;
+import org.springframework.stereotype.Service;
+import java.util.List;
+
+@Service
+public class CommentService {
+    private final CommentRepository commentRepository;
+    private final PostRepository postRepository;
+
+    public CommentService(CommentRepository commentRepository, PostRepository postRepository) {
+        this.commentRepository = commentRepository;
+        this.postRepository = postRepository;
+    }
+
+    public List<Comment> getCommentByPost(Long postId){
+        return commentRepository.findByPost_Id(postId);
+    }
+
+    public Comment addComment(Long postId, Comment comment){
+        Post post = postRepository.findById(postId).orElseThrow(()-> new IllegalArgumentException("게시글 없음"));
+        comment.setPost(post);
+        return commentRepository.save(comment);
+    }
+
+    public void deleteComment(Long id){
+        commentRepository.deleteById(id);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/devSns/service/PostService.java b/src/main/java/com/example/devSns/service/PostService.java
new file mode 100644
index 0000000..e9dce8b
--- /dev/null
+++ b/src/main/java/com/example/devSns/service/PostService.java
@@ -0,0 +1,44 @@
+package com.example.devSns.service;
+
+import com.example.devSns.entity.Post;
+import com.example.devSns.repository.PostRepository;
+import org.springframework.stereotype.Service;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class PostService {
+    private final PostRepository postRepository;
+
+    public PostService(PostRepository postRepository) {
+        this.postRepository = postRepository;
+    }
+
+    public List<Post> findAll(){
+        return postRepository.findAll();
+    }
+
+    public Optional<Post> findById(Long id){
+        return postRepository.findById(id);
+    }
+
+    public Post save(Post post){
+        return postRepository.save(post);
+    }
+    public Post updatePost(Long id, Post updatedPost) {
+        Post existingPost = postRepository.findById(id).orElseThrow(() -> new RuntimeException("Post not found"));
+
+        updatedPost.setCreatedAt(existingPost.getCreatedAt());
+        updatedPost.setUpdatedAt(LocalDateTime.now());
+
+        updatedPost.setId(id);
+
+        return postRepository.save(updatedPost);
+    }
+
+    public void delete(Long id){
+        postRepository.deleteById(id);
+    }
+}
\ No newline at end of file
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index f3f10af..f3fabed 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -1 +1,13 @@
 spring.application.name=devSns
+
+# DB ????
+spring.datasource.url=${DATASOURCE_URL}
+spring.datasource.username=${DATASOURCE_USERNAME}
+spring.datasource.password=${DATASOURCE_PASSWORD}
+# DB ????
+spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
+
+spring.jpa.hibernate.ddl-auto=update
+# true? ???? ?? ???? sql?? ???? ??? ? ????.
+spring.jpa.show-sql=true
+spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
\ No newline at end of file