feat: UserDetailsService CustomService 구현

server/src/main/java/com/ticketing/server/global/service/CustomUserDetailsService.java

@@ -0,0 +1,35 @@
+package com.ticketing.server.global.service;
+
+import com.ticketing.server.user.domain.User;
+import com.ticketing.server.user.domain.repository.UserRepository;
+import java.util.Collections;
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class CustomUserDetailsService implements UserDetailsService {
+
+	private final UserRepository userRepository;
+
+	@Override
+	public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {
+		return userRepository.findByEmailAndIsDeletedFalse(email)
+			.map(this::createUserDetails)
+			.orElseThrow(() -> new UsernameNotFoundException("존재하지 않는 email 입니다. :: " + email));
+	}
+
+	private UserDetails createUserDetails(User user) {
+		SimpleGrantedAuthority grantedAuthority = new SimpleGrantedAuthority(user.getGrade().name());
+
+		return new org.springframework.security.core.userdetails.User(
+			user.getEmail()
+			, user.getPassword()
+			, Collections.singleton(grantedAuthority)
+		);
+	}
+}