feature: 로그인 기능 구현(#32)

feature: 로그인 기능 구현

src/main/java/com/hyunsolution/dangu/user/controller/UserController.java

@@ -0,0 +1,26 @@
+package com.hyunsolution.dangu.user.controller;
+
+import com.hyunsolution.dangu.common.apiResponse.ApiResponse;
+import com.hyunsolution.dangu.user.dto.request.LoginRequest;
+import com.hyunsolution.dangu.user.dto.response.LoginResponse;
+import com.hyunsolution.dangu.user.service.UserService;
+import io.swagger.v3.oas.annotations.Operation;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+public class UserController {
+    private final UserService userService;
+
+    @PostMapping("/users/login")
+    @Operation(summary = "로그인", description = "기존아이디, 비밀번호의 경우 로그인을 진행하며 신규 id의 경우 회원가입을 진행한다.")
+    public ApiResponse<LoginResponse> login(@RequestBody LoginRequest loginRequest) {
+        String uid = loginRequest.getUid();
+        String password = loginRequest.getPassword();
+        LoginResponse id = userService.login(uid, password);
+        return ApiResponse.success(id);
+    }
+}

src/main/java/com/hyunsolution/dangu/user/domain/UserRepository.java

@@ -1,5 +1,8 @@
 package com.hyunsolution.dangu.user.domain;
 
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 
-public interface UserRepository extends JpaRepository<User, Long> {}
+public interface UserRepository extends JpaRepository<User, Long> {
+    Optional<User> findByUid(String uid);
+}

src/main/java/com/hyunsolution/dangu/user/dto/request/LoginRequest.java

@@ -0,0 +1,11 @@
+package com.hyunsolution.dangu.user.dto.request;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class LoginRequest {
+    private String uid;
+    private String password;
+}

src/main/java/com/hyunsolution/dangu/user/dto/response/LoginResponse.java

@@ -0,0 +1,12 @@
+package com.hyunsolution.dangu.user.dto.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+@AllArgsConstructor
+public class LoginResponse {
+    private Long userPk;
+}

src/main/java/com/hyunsolution/dangu/user/exception/UserError.java

@@ -10,7 +10,7 @@
 @AllArgsConstructor
 public enum UserError implements BaseErrorCode {
     USER_NOT_FOUND("USER_400_1", HttpStatus.BAD_REQUEST, "사용자를 찾을 수 없습니다."),
-    ;
+    USER_WRONG_PASSWORD("USER_400_2", HttpStatus.BAD_REQUEST, "비밀번호가 틀렸습니다.");
 
     private final String code;
     private final HttpStatus httpStatus;

src/main/java/com/hyunsolution/dangu/user/exception/UserWrongPasswordException.java

@@ -0,0 +1,12 @@
+package com.hyunsolution.dangu.user.exception;
+
+import com.hyunsolution.dangu.common.exception.CustomException;
+
+public class UserWrongPasswordException extends CustomException {
+    public static final UserWrongPasswordException USER_WRONG_PASSWORD_EXCEPTION =
+            new UserWrongPasswordException();
+
+    private UserWrongPasswordException() {
+        super(UserError.USER_WRONG_PASSWORD);
+    }
+}

src/main/java/com/hyunsolution/dangu/user/service/UserService.java

@@ -0,0 +1,37 @@
+package com.hyunsolution.dangu.user.service;
+
+import com.hyunsolution.dangu.user.domain.User;
+import com.hyunsolution.dangu.user.domain.UserRepository;
+import com.hyunsolution.dangu.user.dto.response.LoginResponse;
+import com.hyunsolution.dangu.user.exception.UserWrongPasswordException;
+import java.util.Optional;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+public class UserService {
+    private final UserRepository userRepository;
+
+    @Transactional
+    // TODO: 왜 트랜잭션 어노테이션을 붙이는지 공부하기(with flush가 언제 일어나나) - 다현
+    public LoginResponse login(String uid, String password) {
+        Optional<User> loginUser = userRepository.findByUid(uid);
+        // 사용자 존재 여부 판단
+        if (loginUser.isEmpty()) {
+            User newUser = registerUser(uid, password);
+            return new LoginResponse(newUser.getId());
+        }
+        // 비밀번호 일치 확인
+        if (loginUser.get().getPassword().equals(password)) {
+            return new LoginResponse(loginUser.get().getId());
+        } else {
+            throw UserWrongPasswordException.USER_WRONG_PASSWORD_EXCEPTION;
+        }
+    }
+
+    public User registerUser(String uid, String password) {
+        return userRepository.save(User.builder().uid(uid).password(password).build());
+    }
+}