[FIXED] How to use RestTemplate with application/octet-stream response type

Issue

I am using a ISBNdB to get info about the books.The reponse type is application/octet-stream. A sample json response I get looks as follows

{
"index_searched" : "isbn",
"data" : [
  {
     "publisher_id" : "john_wiley_sons_inc",
     "publisher_name" : "John Wiley & Sons, Inc",
     "title_latin" : "Java programming interviews exposed",
     "language" : "eng",
     "summary" : "",
     "physical_description_text" : "1 online resource (xvi, 368 pages) :",
     "author_data" : [
        {
           "name" : "Markham, Noel",
           "id" : "markham_noel"
        },
        {
           "id" : "greg_milette",
           "name" : "Greg Milette"
        }
     ],
     "title_long" : "Java programming interviews exposed",
     "urls_text" : "",
     "publisher_text" : "New York; John Wiley & Sons, Inc",
     "book_id" : "java_programming_interviews_exposed",
     "awards_text" : "; ",
     "subject_ids" : [],
     "isbn13" : "9781118722862",
     "lcc_number" : "",
     "title" : "Java programming interviews exposed",
     "isbn10" : "1118722868",
     "dewey_decimal" : "005.13/3",
     "edition_info" : "; ",
     "notes" : "\"Wrox programmer to programmer\"--Cover.; Acceso restringido a usuarios UCM = For UCM patrons only.",
     "marc_enc_level" : "",
     "dewey_normal" : "5.133"
  }
  ]
  }

I am using Jackson to convert this reponse. My Pojo looks as follows

@JsonIgnoreProperties(ignoreUnknown = true)

public class value {
    private  String index_searched;
    // Another pojo in different file with ignore properties
    private data[] dat;

    public value(){

    }
    public data[] getDat() {
        return dat;
    }

    public void setDat(data[] dat) {
        this.dat = dat;
    }
    public String getIndex_searched() {
        return index_searched;
    }
    public void setIndex_searched(String index_searched) {
        this.index_searched = index_searched;
    } 
   }

When I tried following

  value book = restTemplate.getForObject(FINAL_URL, value.class);

I get this exception

org.springframework.web.client.RestClientException: Could not extract response: no suitable HttpMessageConverter found for response type [class com.rocketrenga.mylibrary.domain.value] and content type [application/octet-stream]

But I am able to map the response to String

String book = restTemplate.getForObject(FINAL_URL, String.class);
ObjectMapper mapper = new ObjectMapper();
value val = mapper.readValue(book, value.class);
System.out.println(val.getIndex_searched());

How to go about mapping the response directly POJO instead of String and converting back to POJO

Solution

You need to conifigure restTemplate with message converters. In your configuration do the following:

   @Bean
    public RestOperations restTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();

        
        converter.setSupportedMediaTypes(
                Arrays.asList(new MediaType[]{MediaType.APPLICATION_JSON, MediaType.APPLICATION_OCTET_STREAM}));

        restTemplate.setMessageConverters(Arrays.asList(converter, new FormHttpMessageConverter()));
        return restTemplate;
    }

Answered By - jny
Answer Checked By - Gilberto Lyons (JavaFixing Admin)