Auslösen von ResourceAccessException vs HttpClientErrorException für RestTemplate-Client im Frühjahr

Question

Verwenden von Spring 4.3.1 auf Apache Tomcat 8.5 Wir haben einen REST-Server implementiert, der GET, POST & PUT-Anforderungen verarbeitet. Die POST-Anforderung wird in Form behandelt:

@POST 
@Consumes({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON}) 
@Transactional 
public Response postMethod(final MyDomain object) { 
    domainHandler.createDomain(object); 
    return Response.status(201).entity(object).build(); 
} 

Während POST-Anfrage auf der Serverseite der Handhabung wird die WebApplicationException geworfen, die durch umgegangen wird:

@Provider 
public class WebExceptionMapper implements ExceptionMapper<WebApplicationException> { 
    @Override 
    public Response toResponse(WebApplicationException exception) { 
      int httpStatus = exception.getResponse().getStatus(); 
      ErrorMessage em = new WebErrorMessage(exception.getMessage()); 
      return Response.status(httpStatus).entity(em).build(); 
    } 
} 

Auf der Clientseite:

response = rest.exchange(requestURL, method, requestEntity, MyDomain.class); 

die ResourceAccessException geworfen:

2017-07-25 15:46:41,489 ERROR [com.my.code.web.presentation.ManagementController:63] (http-nio-8080-exec-7#34): Internal exception occured with cause: 
org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://localhost:8080/": Server returned HTTP response code: 500 for URL: http://localhost:8080/; nested exception is java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:8080/ 
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:633) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:580) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:498) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at com.my.code.web.integration.client.rest.FeedbackRestClient.callForApiCreateFeedback(FeedbackRestClient.java:218) ~[classes/:?] 
    at com.my.code.web.integration.client.rest.FeedbackRestClient.pushFeedbackData(FeedbackRestClient.java:70) ~[classes/:?] 
    at com.my.code.web.presentation.FeedbackController.feedback(FeedbackController.java:91) ~[classes/:?] 
    at sun.reflect.GeneratedMethodAccessor72.invoke(Unknown Source) ~[?:?] 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_131] 
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_131] 
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114) ~[spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) [spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) [spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) [spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) [servlet-api.jar:?] 
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [servlet-api.jar:?] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.16] 
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.16] 
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [catalina.jar:8.5.16] 
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [catalina.jar:8.5.16] 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [catalina.jar:8.5.16] 
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) [catalina.jar:8.5.16] 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [catalina.jar:8.5.16] 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [catalina.jar:8.5.16] 
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-coyote.jar:8.5.16] 
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-coyote.jar:8.5.16] 
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-coyote.jar:8.5.16] 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-coyote.jar:8.5.16] 
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-coyote.jar:8.5.16] 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_131] 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_131] 
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.5.16] 
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_131] 
Caused by: java.io.IOException: Server returned HTTP response code: 400 for URL: http://localhost:8080/ 
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1876) ~[?:1.8.0_131] 
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474) ~[?:1.8.0_131] 
    at org.springframework.http.client.SimpleClientHttpResponse.getBody(SimpleClientHttpResponse.java:85) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at com.my.code.web.integration.client.rest.BufferingClientHttpResponseWrapper.getBody(BufferingClientHttpResponseWrapper.java:46) ~[classes/:?] 
    at com.my.code.web.integration.client.rest.LoggingRequestInterceptor.traceResponse(LoggingRequestInterceptor.java:66) ~[classes/:?] 
    at com.my.code.web.integration.client.rest.LoggingRequestInterceptor.intercept(LoggingRequestInterceptor.java:34) ~[classes/:?] 
    at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:85) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:69) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:619) ~[spring-web-4.3.1.RELEASE.jar:4.3.1.RELEASE] 
    ... 47 more 

Frage:

Warum die Ausnahme org.springframework.web.client.ResourceAccessException geworfen wird, aber nicht org.springframework.web.client.HttpClientErrorException, was für den Umgang mit der GET-Anfrage passiert, wenn WebApplicationException auftritt?

Die ResourceAccessException Ausnahme haben keine Methoden, die mir erlauben, den HTTP-Status zu lesen, zB getRawStatusCode(), getResponseHeaders() usw.

Answer 1

Weil es eine IOException Verpackung, nicht an der tatsächlichen Antwortcode suchen.

Die Ursache scheint zu sein, weil BufferingClientHttpResponseWrapper versucht, einen Körper zu lesen, ohne zu prüfen, ob es einen ersten gibt.