diff --git a/src/main/java/com/example/springhw31/controller/UserController.java b/src/main/java/com/example/springhw31/controller/UserController.java
index 7eca68b..ca577aa 100644
--- a/src/main/java/com/example/springhw31/controller/UserController.java
+++ b/src/main/java/com/example/springhw31/controller/UserController.java
@@ -1,16 +1,27 @@
 package com.example.springhw31.controller;
 
 import com.example.springhw31.dto.UserDto;
-import org.springframework.web.bind.annotation.ModelAttribute;
+import com.example.springhw31.service.UserService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
 
 /**
  * 회원가입 메서드처럼 UserDto를 파라미터로 받아주세요
  */
 
+@RestController
+@RequiredArgsConstructor
 public class UserController {
 
+  private final UserService userService;
 
-  public UserDto join(@ModelAttribute UserDto userDto) {
+  @PostMapping("/signup")
+  public UserDto signup(@ModelAttribute UserDto userDto) {
+    return userService.signup(userDto);
+  }
 
+  @GetMapping("/signin")
+  public String signin(@ModelAttribute UserDto userDto) {
+    return userService.signin(userDto);
   }
 }
diff --git a/src/main/java/com/example/springhw31/dto/UserDto.java b/src/main/java/com/example/springhw31/dto/UserDto.java
index 0cb0926..6a6b793 100644
--- a/src/main/java/com/example/springhw31/dto/UserDto.java
+++ b/src/main/java/com/example/springhw31/dto/UserDto.java
@@ -11,9 +11,6 @@
 public class UserDto {
 
   private String username;
-
   private String password;
-
   private String nickname;
-
 }
diff --git a/src/main/java/com/example/springhw31/entity/User.java b/src/main/java/com/example/springhw31/entity/User.java
index 4e957cc..e7186f7 100644
--- a/src/main/java/com/example/springhw31/entity/User.java
+++ b/src/main/java/com/example/springhw31/entity/User.java
@@ -1,14 +1,27 @@
 package com.example.springhw31.entity;
 
 
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+
 /**
  * TODO: 완성된 코드 아닙니다~
  */
+@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;
 }
diff --git a/src/main/java/com/example/springhw31/repository/UserRepository.java b/src/main/java/com/example/springhw31/repository/UserRepository.java
index 53778ec..7a2a3e5 100644
--- a/src/main/java/com/example/springhw31/repository/UserRepository.java
+++ b/src/main/java/com/example/springhw31/repository/UserRepository.java
@@ -1,5 +1,10 @@
 package com.example.springhw31.repository;
 
-public class UserRepository {
+import org.springframework.data.jpa.repository.JpaRepository;
+import com.example.springhw31.entity.User;
 
+import java.util.Optional;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+    Optional<User> findByUsername(String username);
 }
diff --git a/src/main/java/com/example/springhw31/service/UserService.java b/src/main/java/com/example/springhw31/service/UserService.java
index c3e8928..5820fa8 100644
--- a/src/main/java/com/example/springhw31/service/UserService.java
+++ b/src/main/java/com/example/springhw31/service/UserService.java
@@ -1,14 +1,46 @@
 package com.example.springhw31.service;
 
 import com.example.springhw31.dto.UserDto;
+import com.example.springhw31.entity.User;
+import com.example.springhw31.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.NoSuchElementException;
 
 /**
  * Controller에 반환할 때도 DTO 객체를 반환합니다.
  */
+
+@Service
+@RequiredArgsConstructor
 public class UserService {
 
-  public UserDto join(UserDto userDto) {
+  private final UserRepository userRepository;
 
+  //회원가입 로직
+  //아이디, 비밀번호, 닉네임은 null 불가(@Column 사용)
+  //아이디 또는 닉네님이 중복된 경우 회원가입불가
+  public UserDto signup(UserDto userDto) {
+    User user = new User();
+    user.setUsername(userDto.getUsername());
+    user.setPassword(userDto.getPassword());
+    user.setNickname(userDto.getNickname());
+    userRepository.save(user);
+    return userDto;
   }
 
+  //로그인 로직
+  //로그인 성공 시 “{회원 닉네임} 님, 환영합니다!!” 라는 문자열 출력
+  //로그인 실패 시 “아이디 및 비밀번호가 일치하지 않습니다.” 문자열 출력
+  public String signin(UserDto userDto) {
+    User user = userRepository.findByUsername(userDto.getUsername())
+            .orElseThrow(() -> new NoSuchElementException("해당 유저가 없습니다."));
+
+    if(user.getPassword().equals(userDto.getPassword())){
+      return user.getNickname() + "님 환영합니다.!!";
+    }else{
+      return "비밀번호가 일치하지 않습니다.";
+    }
+  }
 }
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index 9b78d0c..5f39bc2 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -1,8 +1,8 @@
 spring:
   datasource:
-    url: jdbc:mysql://localhost:3306/your_database_name?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8
-    username: your_username
-    password: your_password
+    url: jdbc:mysql://localhost:3306/demo?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8
+    username: root
+    password: na58745874@
     driver-class-name: com.mysql.cj.jdbc.Driver
 
   jpa: