로그인 api 사용 중 토큰 값 null 출력, 401 에러가 발생합니다

문의 시, 사용하시는 개발환경과 디벨로퍼스 앱ID를 알려주세요.
___앱 ID 1012404

안녕하세요.
jsp에서 토큰을 요청하기 위해 아래처럼 요청하고 있는데요.

 $.ajax({
            type: 'POST',
            url: '../auth/KakaoLogin.do',
            contentType: 'application/json; charset=utf-8',
            headers: {
                'Authorization': 'Bearer ' + authObj.access_token
            },
            success: function (response) {
                console.log('서버에 전송한 데이터:', JSON.stringify({
                    access_token: authObj.access_token
                }));

콘솔에 엑세스 토큰은 출력되는데 서블릿에서 토큰 값을

String access_token = req.getParameter("access_token");
System.out.println("token : " + access_token);

출력하면 null과 함께 아래처럼 에러 메시지가 출력됩니다. 이전에 토큰을 받은 후 null 값으로 재요청된다고 하셔서 중복된 부분은 수정했습니다.

java.io.IOException: Server returned HTTP response code: 401 for URL: https://kapi.kakao.com/v2/user/me

at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1997)

at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1589)

at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:224)

at servlet.KakaoServiceIml.getUserInfo(KakaoServiceIml.java:103)

at servlet.KakaoLoginAuth.doPost(KakaoLoginAuth.java:47)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:555)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:623)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:209)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)

at servlet.CorsFilter.doFilter(CorsFilter.java:27)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:481)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:670)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:390)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:928)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1794)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)

at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)

at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.base/java.lang.Thread.run(Thread.java:833)

안녕하세요.

백엔드에서 쿼리 파라미터 값을 받도록 구현하셨고

프론트에서는 헤더로 전달하고 있습니다.