Implement more methods in user service

src/main/java/demo/api/user/UserServiceImpl.java

@@ -1,7 +1,10 @@
 package demo.api.user;
 
 import demo.api.user.domain.User;
+import demo.api.user.dtos.UserSignUpRequest;
 import demo.api.user.repository.UserRepository;
+import java.util.List;
+import java.util.Optional;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -10,18 +13,24 @@ import org.springframework.transaction.annotation.Transactional;
 @RequiredArgsConstructor
 @Transactional
 public class UserServiceImpl implements UserService {
-//  private final BCryptPasswordEncoder passwordEncoder;
   private final UserRepository userRepository;
 
   @Override
-  public User signUp(User user) {
-//    user.hashPassword(passwordEncoder);
-    return userRepository.save(user);
+  public User signUp(UserSignUpRequest signUpReq) throws Exception {
+    if(this.isEmailExist(signUpReq.getEmail())) {
+      throw new Exception("Your Mail already Exist.");
+    }
+    return userRepository.save(signUpReq.toUserEntity());
   }
 
   @Override
-  public User findUserByEmail(String email) {
-    return null;
+  public List<User> findAll() {
+    return userRepository.findAll();
+  }
+
+  @Override
+  public Optional<User> findByEmail(String email) {
+    return userRepository.findByEmail(email);
   }
 
   @Override
@@ -29,8 +38,14 @@ public class UserServiceImpl implements UserService {
     return null;
   }
 
-  @Override
-  public boolean isEmailExist(String email) {
-    return false;
+  /**
+   * 이메일 중복 여부를 확인
+   *
+   * @param email
+   * @return true | false
+   */
+  private boolean isEmailExist(String email) {
+    Optional<User> byEmail = userRepository.findByEmail(email);
+    return !byEmail.isEmpty();
   }
 }