Could not extract response: no suitable httpmessageconverter found for response type

Question

Problem :

I am trying to use the curl command as follows:

curl -u 591bf65f50057469f10b5fd9:0cf17f9b03d056ds0e11e48497e506a2 https://backend.tdk.com/api/devicetypes/59147fd79e93s12e61499ffe/messages

But I am getting a JSON response as follows:

{"data":[{"device":"18SE62","time":1494516023,"data":"3235","snr":"36.72",...

I have saved the response on the txt file and parse it using jackson, and everything is fine as below:

ObjectMapper mymapper = new ObjectMapper();

File myfile = new File(getClass().getResource("/result.json").getFile());

MessageList mymessageList = mymapper.readValue(myfile, MessageList.class);

Also I am assuming that I should get the same result using the RestTemplate but that's not the case as below:

RestTemplate myrestTemplate = new RestTemplate();

MessageList mymessageList = 

myrestTemplate.getForObject("http://592693f43c87815f9b8145e9:f099c85d84d4e325a2186c02bd0caeef@backend.tdk.com/api/devicetypes/591570373c87894b4eece34d/messages", MessageList.class);

But I got an error instead as below:

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:88)

at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:711)

at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:520)

at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:114)

at com.tdk.controllers.restful.client.RestTemplateExample.main(RestTemplateExample.java:14)

I also tried to set the contentType as follows:

HttpHeaders myheaders = new HttpHeaders();

myheaders.setContentType(MediaType.APPLICATION_JSON);

HttpEntity<String> myentity = new HttpEntity<String>("parameters", myheaders);

MessageList mymessageList = myrestTemplate.getForObject(myurl, myentity, MessageList.class);

however then I got a compilation error as below

The method getForObject(String, Class<T>, Object...) in the type RestTemplate is not applicable for the arguments (String, HttpEntity<String>,Class<MessageList>)

Answer 1

I was also having the very similar problem, and it turned out to be the very simple; my client was not including the Jackson dependency, even though my code all compiled correctly, but the auto-magic converters for the JSON were not being included in it.

To summarize, I just added a Jackson dependency to my pom.xml and it just worked as follows :

<dependency>

<groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.5.1</version>

</dependency>