JWT認証でHttpClientErrorException: 400 Bad Requestになる

前提・実現したいこと

JWT認証で戻りのJSONを取得したい。

発生している問題・エラーメッセージ

5 28, 2018 5:17:22 午後 org.apache.catalina.core.StandardHostValve custom
重大: Exception Processing ErrorPage[errorCode=500, location=/WEB-INF/html/error/internalServerError.html]
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.web.client.HttpClientErrorException: 400 Bad Request
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:986)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:870)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:472)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:395)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316)
	at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:395)
	at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:254)
	at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:349)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:175)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:486)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)
Caused by: org.springframework.web.client.HttpClientErrorException: 400 Bad Request
	at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94)
	at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:79)
	at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
	at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:777)
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:730)
	at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:686)
	at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:602)
	at test.interceptor.JwtAuthenticationInterceptor.preHandle(WebAuthenticationInterceptor.java:83)
	at org.springframework.web.servlet.HandlerExecutionChain.applyPreHandle(HandlerExecutionChain.java:136)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:986)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
	... 27 more

該当のソースコード

Java
1package test.web.interceptor;
2@Component
3@Scope("request")
4public class JwtAuthenticationInterceptor extends HandlerInterceptorAdapter {
5    @Override
6    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
7        RestTemplate restTemplate = new RestTemplate();
8        HttpHeaders headers = new HttpHeaders();
9        headers.add("Authorization","JWTのアクセストークン値");
10        headers.add("Content-Type", "application/json;charset=UTF-8");
11
12        HttpEntity<String> req = new HttpEntity<String>(headers);
13        ResponseEntity<String> model = restTemplate.exchange(TARGET_URL, HttpMethod.POST, req, String.class); //ここでエラーとなってしまう。
14        return true;
15    }
16}