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:[email protected]/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<String> entity = new HttpEntity<String>("parameters", headers);
MessageList messageList =
restTemplate.getForObject(url, entity, MessageList.class);
but then I got a compilation error
The method getForObject(String, Class<T>, Object...) in the type RestTemplate is not applicable for the arguments (String, HttpEntity<String>,
Class<MessageList>)
I also tried to add a the Jackson Message converter
List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
//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<HttpMessageConverter<?>> 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)
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<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
//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);