diff --git a/KoSeonJe/demo/.gitignore b/KoSeonJe/demo/.gitignore
new file mode 100644
index 0000000..c2065bc
--- /dev/null
+++ b/KoSeonJe/demo/.gitignore
@@ -0,0 +1,37 @@
+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
diff --git a/KoSeonJe/demo/build.gradle b/KoSeonJe/demo/build.gradle
new file mode 100644
index 0000000..4093385
--- /dev/null
+++ b/KoSeonJe/demo/build.gradle
@@ -0,0 +1,35 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '3.1.3'
+	id 'io.spring.dependency-management' version '1.1.3'
+}
+
+group = 'com.example'
+version = '0.0.1-SNAPSHOT'
+
+java {
+	sourceCompatibility = '17'
+}
+
+configurations {
+	compileOnly {
+		extendsFrom annotationProcessor
+	}
+}
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	compileOnly 'org.projectlombok:lombok'
+	runtimeOnly 'com.mysql:mysql-connector-j'
+	annotationProcessor 'org.projectlombok:lombok'
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+}
+
+tasks.named('test') {
+	useJUnitPlatform()
+}
diff --git a/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.jar b/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..033e24c
Binary files /dev/null and b/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.properties b/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..9f4197d
--- /dev/null
+++ b/KoSeonJe/demo/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.2.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/KoSeonJe/demo/gradlew b/KoSeonJe/demo/gradlew
new file mode 100755
index 0000000..fcb6fca
--- /dev/null
+++ b/KoSeonJe/demo/gradlew
@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/KoSeonJe/demo/gradlew.bat b/KoSeonJe/demo/gradlew.bat
new file mode 100644
index 0000000..6689b85
--- /dev/null
+++ b/KoSeonJe/demo/gradlew.bat
@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/KoSeonJe/demo/settings.gradle b/KoSeonJe/demo/settings.gradle
new file mode 100644
index 0000000..0a383dd
--- /dev/null
+++ b/KoSeonJe/demo/settings.gradle
@@ -0,0 +1 @@
+rootProject.name = 'demo'
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/DemoApplication.java b/KoSeonJe/demo/src/main/java/com/example/demo/DemoApplication.java
new file mode 100644
index 0000000..64b538a
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/DemoApplication.java
@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DemoApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(DemoApplication.class, args);
+	}
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/CommentController.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/CommentController.java
new file mode 100644
index 0000000..86d0a05
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/CommentController.java
@@ -0,0 +1,28 @@
+package com.example.demo.comment.controller;
+
+import com.example.demo.comment.controller.request.CreateCommentRequest;
+import com.example.demo.comment.service.CommentService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/members/{memberId}/posts/{postId}/comments")
+public class CommentController {
+
+  private final CommentService commentService;
+
+  @PostMapping
+  public void createComment(
+      @RequestBody CreateCommentRequest createCommentRequest,
+      @PathVariable("memberId") Long memberId,
+      @PathVariable("postId") Long postId
+  ) {
+    commentService.createComment(createCommentRequest, memberId, postId);
+  }
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/request/CreateCommentRequest.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/request/CreateCommentRequest.java
new file mode 100644
index 0000000..81ed7ea
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/request/CreateCommentRequest.java
@@ -0,0 +1,22 @@
+package com.example.demo.comment.controller.request;
+
+import com.example.demo.comment.domain.Comment;
+import com.example.demo.member.domain.Member;
+import com.example.demo.post.domain.Post;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class CreateCommentRequest {
+
+  private String content;
+
+  public Comment toEntity(Member member, Post post){
+    return Comment.builder()
+        .content(content)
+        .member(member)
+        .post(post)
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/response/AllCommentsResponse.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/response/AllCommentsResponse.java
new file mode 100644
index 0000000..93665b8
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/controller/response/AllCommentsResponse.java
@@ -0,0 +1,25 @@
+package com.example.demo.comment.controller.response;
+
+import com.example.demo.comment.domain.Comment;
+import com.example.demo.post.controller.response.AllPostsResponse;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class AllCommentsResponse {
+
+  private String content;
+
+  @Builder
+  private AllCommentsResponse(String content) {
+    this.content = content;
+  }
+
+  public static AllCommentsResponse from(Comment comment){
+    return AllCommentsResponse.builder()
+        .content(comment.getContent())
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/domain/Comment.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/domain/Comment.java
new file mode 100644
index 0000000..5aa0f3b
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/domain/Comment.java
@@ -0,0 +1,48 @@
+package com.example.demo.comment.domain;
+
+import com.example.demo.comment.controller.request.CreateCommentRequest;
+import com.example.demo.member.domain.Member;
+import com.example.demo.post.domain.Post;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+public class Comment {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  @Column(name = "comment_id")
+  private Long commentId;
+
+  private String content;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "member_id")
+  private Member member;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "post_id")
+  private Post post;
+
+  @Builder
+  private Comment(String content, Member member, Post post){
+    this.content = content;
+    this.member = member;
+    this.post = post;
+  }
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/repository/CommentRepository.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/repository/CommentRepository.java
new file mode 100644
index 0000000..d78c1ea
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/repository/CommentRepository.java
@@ -0,0 +1,9 @@
+package com.example.demo.comment.repository;
+
+import com.example.demo.comment.domain.Comment;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/comment/service/CommentService.java b/KoSeonJe/demo/src/main/java/com/example/demo/comment/service/CommentService.java
new file mode 100644
index 0000000..a7f73e4
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/comment/service/CommentService.java
@@ -0,0 +1,29 @@
+package com.example.demo.comment.service;
+
+import com.example.demo.comment.controller.request.CreateCommentRequest;
+import com.example.demo.comment.domain.Comment;
+import com.example.demo.comment.repository.CommentRepository;
+import com.example.demo.member.domain.Member;
+import com.example.demo.member.service.MemberService;
+import com.example.demo.post.domain.Post;
+import com.example.demo.post.service.PostService;
+import org.springframework.transaction.annotation.Transactional;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+@Transactional
+public class CommentService {
+
+  private final CommentRepository commentRepository;
+  private final MemberService memberService;
+  private final PostService postService;
+
+  public void createComment(CreateCommentRequest createCommentRequest, Long memberId, Long postId) {
+    Member member = memberService.findOneUser(memberId);
+    Post post = postService.findOnePost(postId);
+    Comment comment = createCommentRequest.toEntity(member, post);
+    commentRepository.save(comment);
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/MemberController.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/MemberController.java
new file mode 100644
index 0000000..fc76e79
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/MemberController.java
@@ -0,0 +1,39 @@
+package com.example.demo.member.controller;
+
+import com.example.demo.member.controller.request.CreateMemberRequest;
+import com.example.demo.member.controller.request.UpdateMemberRequest;
+import com.example.demo.member.controller.response.MemberResponse;
+import com.example.demo.member.service.MemberService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/members")
+public class MemberController {
+
+  private final MemberService memberService;
+
+  @PostMapping
+  public void createUser(@RequestBody CreateMemberRequest createMemberRequest) {
+    memberService.createUser(createMemberRequest);
+  }
+
+  @PutMapping(value = "/{memberId}")
+  public void updateUserInfo(
+      @PathVariable Long memberId,
+      @RequestBody UpdateMemberRequest updateMemberRequest) {
+    memberService.updateUserInfo(memberId, updateMemberRequest);
+  }
+
+  @GetMapping(value = "/{memberId}")
+  public MemberResponse getMemberInfo(@PathVariable Long memberId) {
+    return memberService.getMemberInfo(memberId);
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/CreateMemberRequest.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/CreateMemberRequest.java
new file mode 100644
index 0000000..0fde4ea
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/CreateMemberRequest.java
@@ -0,0 +1,21 @@
+package com.example.demo.member.controller.request;
+
+import com.example.demo.member.domain.Member;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class CreateMemberRequest {
+
+  private String authId;
+
+  private String name;
+
+  public Member toEntity(){
+    return Member.builder()
+        .authId(authId)
+        .name(name)
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/UpdateMemberRequest.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/UpdateMemberRequest.java
new file mode 100644
index 0000000..b7af01f
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/request/UpdateMemberRequest.java
@@ -0,0 +1,13 @@
+package com.example.demo.member.controller.request;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class UpdateMemberRequest {
+
+  private String authId;
+
+  private String name;
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/response/MemberResponse.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/response/MemberResponse.java
new file mode 100644
index 0000000..088204a
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/controller/response/MemberResponse.java
@@ -0,0 +1,27 @@
+package com.example.demo.member.controller.response;
+
+import com.example.demo.member.domain.Member;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class MemberResponse {
+  private String authId;
+
+  private String name;
+
+  @Builder
+  private MemberResponse(String authId, String name) {
+    this.authId = authId;
+    this.name = name;
+  }
+
+  public static MemberResponse from(Member member){
+    return MemberResponse.builder()
+        .authId(member.getAuthId())
+        .name(member.getName())
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/domain/Member.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/domain/Member.java
new file mode 100644
index 0000000..cc73c8e
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/domain/Member.java
@@ -0,0 +1,48 @@
+package com.example.demo.member.domain;
+
+import com.example.demo.member.controller.request.CreateMemberRequest;
+import com.example.demo.post.domain.Post;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+import java.util.ArrayList;
+import java.util.List;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+public class Member {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  @Column(name = "member_id")
+  private Long memberId;
+
+  @Column(unique = true, nullable = false)
+  private String authId;
+
+  private String name;
+
+  @OneToMany(mappedBy = "member")
+  private List<Post> posts = new ArrayList<>();
+
+  @Builder
+  private Member(String authId, String name) {
+    this.authId = authId;
+    this.name = name;
+  }
+
+  public void update(String authId, String name) {
+    this.authId = authId;
+    this.name = name;
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/repository/MemberRepository.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/repository/MemberRepository.java
new file mode 100644
index 0000000..b29f258
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/repository/MemberRepository.java
@@ -0,0 +1,8 @@
+package com.example.demo.member.repository;
+
+import com.example.demo.member.domain.Member;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface MemberRepository extends JpaRepository<Member, Long> {
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/member/service/MemberService.java b/KoSeonJe/demo/src/main/java/com/example/demo/member/service/MemberService.java
new file mode 100644
index 0000000..43a2760
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/member/service/MemberService.java
@@ -0,0 +1,40 @@
+package com.example.demo.member.service;
+
+import com.example.demo.member.controller.request.CreateMemberRequest;
+import com.example.demo.member.controller.request.UpdateMemberRequest;
+import com.example.demo.member.controller.response.MemberResponse;
+import com.example.demo.member.domain.Member;
+import com.example.demo.member.repository.MemberRepository;
+import org.springframework.transaction.annotation.Transactional;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@Service
+@Transactional
+@RequiredArgsConstructor
+public class MemberService {
+
+  private final MemberRepository memberRepository;
+
+  public void createUser(CreateMemberRequest createMemberRequest) {
+    Member member = createMemberRequest.toEntity();
+    memberRepository.save(member);
+  }
+
+  public void updateUserInfo(Long memberId, UpdateMemberRequest updateMemberRequest) {
+    Member member = findOneUser(memberId);
+    member.update(updateMemberRequest.getAuthId(), updateMemberRequest.getName());
+  }
+
+  @Transactional(readOnly = true)
+  public MemberResponse getMemberInfo(Long memberId) {
+    Member member = findOneUser(memberId);
+    return MemberResponse.from(member);
+  }
+
+  @Transactional(readOnly = true)
+  public Member findOneUser(Long memberId) {
+    return memberRepository.findById(memberId)
+        .orElseThrow(() -> new IllegalArgumentException("존재하지 않는 아이디입니다."));
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/PostController.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/PostController.java
new file mode 100644
index 0000000..7fcb2d1
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/PostController.java
@@ -0,0 +1,47 @@
+package com.example.demo.post.controller;
+
+import com.example.demo.post.controller.request.CreatePostRequest;
+import com.example.demo.post.controller.response.AllPostsResponse;
+import com.example.demo.post.controller.response.OnePostResponse;
+import com.example.demo.post.service.PostService;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/members")
+public class PostController {
+
+  private final PostService postService;
+
+  @GetMapping("/posts/{postId}")
+  public OnePostResponse getOnePost(@PathVariable("postId") Long postId) {
+    return postService.getOnePost(postId);
+  }
+
+  @GetMapping("/posts")
+  public List<AllPostsResponse> getAllPost() {
+    return postService.getAllPosts();
+  }
+
+  @PostMapping("/{memberId}/posts")
+  public void createPost(
+      @RequestBody CreatePostRequest createPostRequest,
+      @PathVariable("memberId") Long memberId) {
+    postService.createPost(createPostRequest, memberId);
+  }
+
+  @DeleteMapping("/{memberId}/posts/{postId}")
+  public void deletePost(@PathVariable("postId") Long postId) {
+    postService.deletePost(postId);
+  }
+
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/request/CreatePostRequest.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/request/CreatePostRequest.java
new file mode 100644
index 0000000..6777196
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/request/CreatePostRequest.java
@@ -0,0 +1,22 @@
+package com.example.demo.post.controller.request;
+
+import com.example.demo.member.domain.Member;
+import com.example.demo.post.domain.Post;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class CreatePostRequest {
+
+  private String title;
+  private String content;
+
+  public Post toEntity(Member member){
+    return Post.builder()
+        .title(title)
+        .content(content)
+        .member(member)
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/AllPostsResponse.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/AllPostsResponse.java
new file mode 100644
index 0000000..5da179b
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/AllPostsResponse.java
@@ -0,0 +1,34 @@
+package com.example.demo.post.controller.response;
+
+import com.example.demo.post.domain.Post;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class AllPostsResponse {
+  //게시글의 id, 게시글의 제목, 작성자의 이름, 게시글의 댓글 개수를 리스트로 반환
+
+  private Long postId;
+  private String title;
+  private String author;
+  private int commentCount;
+
+  @Builder
+  private AllPostsResponse(Long postId, String title, String author, int commentCount) {
+    this.postId = postId;
+    this.title = title;
+    this.author = author;
+    this.commentCount = commentCount;
+  }
+
+  public static AllPostsResponse from(Post post) {
+    return AllPostsResponse.builder()
+        .postId(post.getPostId())
+        .title(post.getTitle())
+        .author(post.getMember().getName())
+        .commentCount(post.getComments().size())
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/OnePostResponse.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/OnePostResponse.java
new file mode 100644
index 0000000..281ad11
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/controller/response/OnePostResponse.java
@@ -0,0 +1,41 @@
+package com.example.demo.post.controller.response;
+
+import com.example.demo.comment.controller.response.AllCommentsResponse;
+import com.example.demo.comment.domain.Comment;
+import com.example.demo.post.domain.Post;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class OnePostResponse {
+
+  private String title;
+  private String content;
+  private String author;
+  private String createdDate;
+  private List<AllCommentsResponse> allCommentsResponse;
+
+  @Builder
+  private OnePostResponse(String title, String content, String author, String createdDate, List<AllCommentsResponse> allCommentsResponse) {
+    this.title = title;
+    this.content = content;
+    this.author = author;
+    this.createdDate = createdDate;
+    this.allCommentsResponse = allCommentsResponse;
+  }
+
+  public static OnePostResponse from(Post post) {
+    return OnePostResponse.builder()
+        .title(post.getTitle())
+        .content(post.getContent())
+        .author(post.getMember().getName())
+        .createdDate(post.getCreatedDate().toString())
+        .allCommentsResponse(post.getAllComment())
+        .build();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/domain/Post.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/domain/Post.java
new file mode 100644
index 0000000..4753f56
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/domain/Post.java
@@ -0,0 +1,64 @@
+package com.example.demo.post.domain;
+
+import com.example.demo.comment.controller.response.AllCommentsResponse;
+import com.example.demo.comment.domain.Comment;
+import com.example.demo.member.domain.Member;
+import com.example.demo.post.controller.request.CreatePostRequest;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import org.hibernate.annotations.CreationTimestamp;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+public class Post {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  @Column(name = "post_id")
+  private Long postId;
+
+  private String title;
+
+  private String content;
+
+  @CreationTimestamp
+  private LocalDateTime createdDate;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "member_id")
+  private Member member;
+
+  @OneToMany(mappedBy = "post", cascade = CascadeType.ALL)
+  private List<Comment> comments = new ArrayList<>();
+
+  @Builder
+  private Post(String title, String content, Member member) {
+    this.title = title;
+    this.content = content;
+    this.member = member;
+  }
+
+  public List<AllCommentsResponse> getAllComment() {
+    return getComments().stream()
+        .map(AllCommentsResponse::from).toList();
+  }
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/repository/PostRepository.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/repository/PostRepository.java
new file mode 100644
index 0000000..0cb1bbe
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/repository/PostRepository.java
@@ -0,0 +1,8 @@
+package com.example.demo.post.repository;
+
+import com.example.demo.post.domain.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PostRepository extends JpaRepository<Post, Long> {
+
+}
diff --git a/KoSeonJe/demo/src/main/java/com/example/demo/post/service/PostService.java b/KoSeonJe/demo/src/main/java/com/example/demo/post/service/PostService.java
new file mode 100644
index 0000000..5f151b5
--- /dev/null
+++ b/KoSeonJe/demo/src/main/java/com/example/demo/post/service/PostService.java
@@ -0,0 +1,57 @@
+package com.example.demo.post.service;
+
+import com.example.demo.member.domain.Member;
+import com.example.demo.member.service.MemberService;
+import com.example.demo.post.controller.request.CreatePostRequest;
+import com.example.demo.post.controller.response.AllPostsResponse;
+import com.example.demo.post.controller.response.OnePostResponse;
+import com.example.demo.post.domain.Post;
+import com.example.demo.post.repository.PostRepository;
+import org.springframework.transaction.annotation.Transactional;
+import java.util.List;
+import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@Service
+@Transactional
+@RequiredArgsConstructor
+public class PostService {
+
+  private final PostRepository postRepository;
+
+  private final MemberService memberService;
+
+  public void createPost(CreatePostRequest createPostRequest, Long memberId) {
+    Member member = memberService.findOneUser(memberId);
+    Post post = createPostRequest.toEntity(member);
+    postRepository.save(post);
+  }
+
+  @Transactional(readOnly = true)
+  public OnePostResponse getOnePost(Long postId) {
+    Post post = findOnePost(postId);
+    return OnePostResponse.from(post);
+
+  }
+
+  @Transactional(readOnly = true)
+  public List<AllPostsResponse> getAllPosts() {
+    List<Post> allPosts = postRepository.findAll();
+    List<AllPostsResponse> allPostsResponse = allPosts.stream()
+        .map(AllPostsResponse::from)
+        .collect(Collectors.toList());
+    return allPostsResponse;
+  }
+
+  public void deletePost(Long postId) {
+    Post post = findOnePost(postId);
+    postRepository.delete(post);
+  }
+
+  @Transactional(readOnly = true)
+  public Post findOnePost(Long postId) {
+    return postRepository.findById(postId)
+        .orElseThrow(() -> new IllegalArgumentException("존재하지 않은 게시물입니다."));
+  }
+}
diff --git a/KoSeonJe/demo/src/main/resources/application.yml b/KoSeonJe/demo/src/main/resources/application.yml
new file mode 100644
index 0000000..e9aac99
--- /dev/null
+++ b/KoSeonJe/demo/src/main/resources/application.yml
@@ -0,0 +1,18 @@
+spring:
+  datasource:
+    url: jdbc:mysql://localhost:3306/cow?createDatabaseIfNotExist=true
+    driver-class-name: com.mysql.cj.jdbc.Driver
+    username: root
+    password: 1234
+
+
+  jpa:
+    hibernate:
+      ddl-auto: create
+    properties:
+      hibernate:
+        show_sql: true
+        format_sql: true
+
+server:
+  port: 9090
\ No newline at end of file
diff --git a/KoSeonJe/demo/src/test/java/com/example/demo/DemoApplicationTests.java b/KoSeonJe/demo/src/test/java/com/example/demo/DemoApplicationTests.java
new file mode 100644
index 0000000..2778a6a
--- /dev/null
+++ b/KoSeonJe/demo/src/test/java/com/example/demo/DemoApplicationTests.java
@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class DemoApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}