feat: JwtAuthenticationEntryPoint 커스텀 에러 반환 설정 (#63)

src/main/java/com/project/mapdagu/jwt/JwtAuthenticationEntryPoint.java

@@ -1,5 +1,7 @@
 package com.project.mapdagu.jwt;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.project.mapdagu.error.dto.ErrorResponse;
 import jakarta.servlet.ServletException;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
@@ -10,17 +12,31 @@
 
 import java.io.IOException;
 
+import static com.project.mapdagu.error.ErrorCode.NOT_AUTHENTICATED_REQUEST;
+
 /**
  * 유효한 자격 증명을 제공하지 않고 접근하려 할 때, 401 UnAuthorized 에러를 리턴
  */
 @Slf4j
 @Component
 public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {
 
+    private final ObjectMapper objectMapper;
+
+    public JwtAuthenticationEntryPoint(ObjectMapper objectMapper) {
+        this.objectMapper = objectMapper;
+    }
+
     @Override
     public void commence(HttpServletRequest request, HttpServletResponse response,
                          AuthenticationException authException) throws IOException, ServletException {
         log.info("인증되지 않은 요청입니다.");
-        response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
+        ErrorResponse errorResponse = ErrorResponse.of(NOT_AUTHENTICATED_REQUEST.getCode(), NOT_AUTHENTICATED_REQUEST.getMessage());
+        String jsonResponse = objectMapper.writeValueAsString(errorResponse);
+
+        response.setContentType("application/json");
+        response.setCharacterEncoding("UTF-8");
+        response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
+        response.getWriter().write(jsonResponse);
     }
 }