토큰을 사용하여 현재 사용자 정보 응답

src/main/java/com/example/vue/domain/user/UserController.java

@@ -11,7 +11,10 @@ import org.springframework.web.bind.annotation.RestController;
 @RequiredArgsConstructor
 public class UserController {
 
+    private final UserService userService;
+
     @GetMapping
-    public void getAuthenticationUser(@AuthenticationPrincipal User user) {
+    public UserResponseDto getAuthenticationUser(@AuthenticationPrincipal User user) {
+        return new UserResponseDto(userService.findById(user.getId()));
     }
 }

src/main/java/com/example/vue/domain/user/UserException.java

@@ -0,0 +1,16 @@
+package com.example.vue.domain.user;
+
+import java.util.function.Supplier;
+
+public class UserException {
+
+    public static class NoExist extends RuntimeException {
+        public NoExist(Long id) {
+            super("존재하지 않는 사용자입니다. [userId=" + id + "]");
+        }
+    }
+
+    public static Supplier<NoExist> passNoExistExceptionSupplier(Long id) {
+        return () -> new NoExist(id);
+    }
+}

src/main/java/com/example/vue/domain/user/UserRepository.java

@@ -5,6 +5,7 @@ import org.springframework.stereotype.Repository;
 
 import javax.persistence.EntityManager;
 import java.util.List;
+import java.util.Optional;
 
 @Repository
 @RequiredArgsConstructor
@@ -21,4 +22,8 @@ public class UserRepository {
         return em.createNamedQuery("findByEmail", User.class).setParameter("email", email).getResultList();
     }
 
+    public Optional<User> findById(Long id) {
+        return Optional.ofNullable(em.find(User.class, id));
+    }
+
 }

src/main/java/com/example/vue/domain/user/UserResponseDto.java

@@ -0,0 +1,21 @@
+package com.example.vue.domain.user;
+
+import lombok.Data;
+
+import java.time.LocalDateTime;
+
+@Data
+public class UserResponseDto {
+
+    private Long id;
+    private String email;
+    private String name;
+    private LocalDateTime createdAt;
+
+    public UserResponseDto(User user) {
+        this.id = user.getId();
+        this.email = user.getEmail();
+        this.name = user.getName();
+        this.createdAt = user.getCreatedAt();
+    }
+}

src/main/java/com/example/vue/domain/user/UserService.java

@@ -1,7 +1,15 @@
 package com.example.vue.domain.user;
 
+import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
 @Service
+@RequiredArgsConstructor
 public class UserService {
+
+    private final UserRepository userRepository;
+
+    public User findById(Long id) {
+        return userRepository.findById(id).orElseThrow(UserException.passNoExistExceptionSupplier(id));
+    }
 }