RestClientException Could not extract response no suitable HttpMessageConverter found

Question

Using the curl command   curl -u 591bf65f50057469f10b5fd9 0cf17f9b03d056ds0e11e48497e506a2 https   backend tdk com api devicetypes 59147fd79e93s12e61499ffe messages   I am getting a JSON response     data     device   18SE62   time  1494516023  data   3235   snr   36 72        I save the response on a txt file and parse it using jackson  and everything is fine  ObjectMapper mapper   new ObjectMapper            File f   new File getClass   getResource                        result json   getFile             MessageList messageList   mapper readValue f  MessageList class     and I assume I should get the same result using RestTemplate but that s not the case  RestTemplate restTemplate   new RestTemplate            MessageList messageList                    restTemplate getForObject  http   592693f43c87815f9b8145e9 f099c85d84d4e325a2186c02bd0caeef backend tdk com api devicetypes 591570373c87894b4eece34d messages   MessageList class     I got an error instead  Exception in thread  main  org springframework web client RestClientException  Could not extract response  no suitable HttpMessageConverter found for response type  class com tdk domain backend MessageList  and content type  text html charset iso-8859-1      at org springframework web client HttpMessageConverterExtractor extractData HttpMessageConverterExtractor java 109      at org springframework web client RestTemplate doExecute RestTemplate java 655      at org springframework web client RestTemplate execute RestTemplate java 613      at org springframework web client RestTemplate getForObject RestTemplate java 287      at com tdk controllers restful client RestTemplateExample main RestTemplateExample java 27    I tried to set the contentType   HttpHeaders headers   new HttpHeaders            headers setContentType MediaType APPLICATION JSON           HttpEntity lt String gt  entity   new HttpEntity lt String gt   parameters   headers             MessageList messageList                    restTemplate getForObject url  entity  MessageList class     but then I got a compilation error  The method getForObject String  Class lt T gt   Object     in the type RestTemplate is not applicable for the arguments  String  HttpEntity lt String gt     Class lt MessageList gt     I also tried to add a the Jackson Message converter    List lt HttpMessageConverter lt   gt  gt  messageConverters   new ArrayList lt HttpMessageConverter lt   gt  gt                           Add the Jackson Message converter             messageConverters add new MappingJackson2HttpMessageConverter                       Add the message converters to the restTemplate             restTemplate setMessageConverters messageConverters                 MessageList messageList                        restTemplate getForObject url  MessageList class     But then I got this error   Exception in thread  main  org springframework web client RestClientException  Could not extract response  no suitable HttpMessageConverter found for response type  class com tdk domain backend MessageList  and content type  text html charset iso-8859-1      at org springframework web client HttpMessageConverterExtractor extractData HttpMessageConverterExtractor java 109      at org springframework web client RestTemplate doExecute RestTemplate java 655      at org springframework web client RestTemplate execute RestTemplate java 613      at org springframework web client RestTemplate getForObject RestTemplate java 287      at com tdk controllers restful client RestTemplateExample main RestTemplateExample java 51    I also tried adding the class   Configuration  EnableWebMvc public class MvcConf extends WebMvcConfigurationSupport        protected void configureMessageConverters List lt HttpMessageConverter lt   gt  gt  converters            converters add converter             addDefaultHttpMessageConverters converters               Bean     MappingJackson2HttpMessageConverter converter              MappingJackson2HttpMessageConverter converter                        new MappingJackson2HttpMessageConverter            return converter             but I got the error   org springframework web client RestClientException  Could not extract response  no suitable HttpMessageConverter found for response type  class com tdk domain backend MessageList  and content type  text html charset iso-8859-1      at org springframework web client HttpMessageConverterExtractor extractData HttpMessageConverterExtractor java 109      at org springframework web client RestTemplate doExecute RestTemplate java 655      at org springframework web client RestTemplate execute RestTemplate java 613      at org springframework web client RestTemplate getForObject RestTemplate java 287

User · Answer

Please add the shared dependency having jackson databind package   Hope this will clear the issue     lt dependency gt         lt groupId gt com fasterxml jackson core lt  groupId gt         lt artifactId gt jackson-databind lt  artifactId gt         lt version gt 2 12 1 lt  version gt     lt  dependency gt

User · Answer

I was trying to use Feign  while I encounter same issue  As I understood HTTP message converter will help but wanted to understand how to achieve this   FeignClient name    quot mobilesearch quot   url    quot   mobile search uri  quot            fallbackFactory   MobileSearchFallbackFactory class          configuration   MobileSearchFeignConfig class  public interface MobileSearchClient         RequestMapping method   RequestMethod GET      List lt MobileSearchResponse gt  getPhones       You have to use Customer Configuration for the decoder  MobileSearchFeignConfig  public class MobileSearchFeignConfig         Bean     Logger Level feignLoggerLevel             return Logger Level FULL               Bean     public Decoder feignDecoder             return new ResponseEntityDecoder new SpringDecoder feignHttpMessageConverter                 public ObjectFactory lt HttpMessageConverters gt  feignHttpMessageConverter             final HttpMessageConverters httpMessageConverters   new HttpMessageConverters new MappingJackson2HttpMessageConverter             return new ObjectFactory lt HttpMessageConverters gt                   Override             public HttpMessageConverters getObject   throws BeansException                   return httpMessageConverters                                      public class MappingJackson2HttpMessageConverter extends org springframework http converter json MappingJackson2HttpMessageConverter           MappingJackson2HttpMessageConverter                 List lt MediaType gt  mediaTypes   new ArrayList lt  gt                 mediaTypes add MediaType valueOf MediaType TEXT HTML VALUE    quot  charset UTF-8 quot                 setSupportedMediaTypes mediaTypes

User · Answer

In my case  Ilya Dyoshin s solution didn t work  The mediatype     was not allowed  I fix this error by adding a new converter to the restTemplate this way during initialization of the MockRestServiceServer     MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter                          new MappingJackson2HttpMessageConverter      mappingJackson2HttpMessageConverter setSupportedMediaTypes                                      Arrays asList                                         MediaType APPLICATION JSON                                          MediaType APPLICATION OCTET STREAM      restTemplate getMessageConverters   add mappingJackson2HttpMessageConverter     mockServer   MockRestServiceServer createServer restTemplate      Based on the solution proposed by Yashwant Chavan on the blog named technicalkeeda   JN Gerbaux

User · Answer

The main problem here is content type  text html charset iso-8859-1  received from the service  however the real content type should be application json charset iso-8859-1   In order to overcome this you can introduce custom message converter  and register it for all kind of responses  i e  ignore the response content type header   Just like this   List lt HttpMessageConverter lt   gt  gt  messageConverters   new ArrayList lt HttpMessageConverter lt   gt  gt               Add the Jackson Message converter MappingJackson2HttpMessageConverter converter   new MappingJackson2HttpMessageConverter        Note  here we are making this converter to process any kind of response      not only application  json  which is the default behaviour converter setSupportedMediaTypes Collections singletonList MediaType ALL            messageConverters add converter     restTemplate setMessageConverters messageConverters

User · Answer

Spring sets the default content-type to octet-stream when the response is missing that field  All you need to do is to add a message converter to fix this

User · Answer

Here is the approach I follow whenever I see this type of error   One way to debug this issue is by first taking whatever response is coming as String class then applying Gson   fromJson StringResp body    MyDTO class   It will still fail most probably but this time it will throw the fields which are creating this error to happen in first place  Post the modification  we can use the previous approach as usual   ResponseEntity lt String gt  respStr   restTemplate exchange URL HttpMethod GET  entity   String class   Gson g   new Gson    The below step will throw error with the fields which is causing the issue MyDTO resp   g fromJson respStr getBody    MyDTO class    I don t have the error message with me but it will point to the field which is problematic and the reason for it  Resolve those and try again with previous approach

User · Answer

You need to create your own converter and implement it before making a GET request   RestTemplate  restTemplate   new RestTemplate     List lt HttpMessageConverter lt   gt  gt  messageConverters   new ArrayList lt HttpMessageConverter lt   gt  gt              MappingJackson2HttpMessageConverter converter   new MappingJackson2HttpMessageConverter    converter setSupportedMediaTypes Collections singletonList MediaType ALL             messageConverters add converter     restTemplate setMessageConverters messageConverters

User · Answer

While the accepted answer solved the OP s original problem  most people finding this question through a Google search are likely having an entirely different problem which just happens to throw the same no suitable HttpMessageConverter found exception  What happens under the covers is that MappingJackson2HttpMessageConverter swallows any exceptions that occur in its canRead   method  which is supposed to auto-detect whether the payload is suitable for json decoding  The exception is replaced by a simple boolean return that basically communicates sorry  I don t know how to decode this message to the higher level APIs  RestClient   Only after all other converters  canRead   methods return false  the no suitable HttpMessageConverter found exception is thrown by the higher-level API  totally obscuring the true problem  For people who have not found the root cause  like you and me  but not the OP   the way to troubleshoot this problem is to place a debugger breakpoint on onMappingJackson2HttpMessageConverter canRead    then enable a general breakpoint on any exception  and hit Continue  The next exception is the true root cause  My specific error happened to be that one of the beans referenced an interface that was missing the proper deserialization annotations  UPDATE FROM THE FUTURE This has proven to be such a recurring issue across so many of my projects  that I ve developed a more proactive solution  Whenever I have a need to process JSON exclusively  no XML or other formats   I now replace my RestTemplate bean with an instance of the following  public class JsonRestTemplate extends RestTemplate        public JsonRestTemplate              ClientHttpRequestFactory clientHttpRequestFactory            super clientHttpRequestFactory               Force a sensible JSON mapper             Customize as needed for your project s definition of  quot sensible quot           ObjectMapper objectMapper   new ObjectMapper                    registerModule new Jdk8Module                     registerModule new JavaTimeModule                     configure                          SerializationFeature WRITE DATES AS TIMESTAMPS  false            List lt HttpMessageConverter lt   gt  gt  messageConverters   new ArrayList lt  gt             MappingJackson2HttpMessageConverter jsonMessageConverter   new MappingJackson2HttpMessageConverter                  public boolean canRead java lang Class lt   gt  clazz                      org springframework http MediaType mediaType                    return true                                public boolean canRead java lang reflect Type type                      java lang Class lt   gt  contextClass                      org springframework http MediaType mediaType                    return true                            protected boolean canRead                      org springframework http MediaType mediaType                    return true                                    jsonMessageConverter setObjectMapper objectMapper           messageConverters add jsonMessageConverter           super setMessageConverters messageConverters             This customization makes the RestClient incapable of understanding anything other than JSON  The upside is that any error messages that may occur will be much more explicit about what s wrong

User · Answer

In my case it was caused by the absence of the jackson-core  jackson-annotations and jackson-databind jars from the runtime classpath  It did not complain with the usual ClassNothFoundException as one would expect but rather with the error mentioned in the original question

User · Answer

If the above response by  Ilya Dyoshin didn t still retrieve   try to get the response into a String Object    For my self thought the error got solved by the code snippet by Ilya  the response retrieved was a failure error  from the server    HttpHeaders requestHeaders   new HttpHeaders    requestHeaders add HttpHeaders CONTENT TYPE   application x-www-form-urlencoded    ResponseEntity lt String gt  st   restTemplate exchange url  HttpMethod POST  httpEntity  String class      And Cast to the ResponseObject DTO  Json    Gson g   new Gson    DTO dto   g fromJson st getBody    DTO class

User · Answer

I was having a very similar problem  and it turned out to be quite simple  my client wasn t including a Jackson dependency  even though the code all compiled correctly  the auto-magic converters for JSON weren t being included  See this RestTemplate-related solution   In short  I added a Jackson dependency to my pom xml and it just worked    lt dependency gt       lt groupId gt com fasterxml jackson core lt  groupId gt       lt artifactId gt jackson-databind lt  artifactId gt       lt version gt 2 5 1 lt  version gt   lt  dependency gt

User · Answer

Other possible solution   I tried to map the result of a restTemplate getForObject with a private class instance  defined inside of my working class   It did not work  but if I define the object to public  inside its own file  it worked correctly

[json] RestClientException: Could not extract response. no suitable HttpMessageConverter found

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