Consuming HAL-based REST service with spring-hateoas

Question

I\'m trying to consume a HAL-based REST service with the RestTemplate class. The response body looks like this:

{
  \"_embedded\": {
    \"school:teachers\":         


        

Answer 1

I tried a similar approach to what Vishnoo Rath. I am planning to build a common method to do this for all my resources.

ResponseEntity<String> response = 
                restTemplate.exchange("http://localhost:8081/rest/cars", HttpMethod.GET, null, String.class);

        String data = response.getBody();
        //log.info(data);

        ObjectMapper om = new ObjectMapper();
        om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        JsonNode jsNode = om.readTree(data);
        String test = jsNode.at("/_embedded/cars").toString();
        //log.info(test);

        ArrayList<Car> cars = om.readValue(test, new TypeReference<List<Car>>() {
        });

        for (Car theCar : cars) {
            log.info(">>> " + theCar.getMake() + " " + theCar.getModel() + " " + theCar.getYear());
        }

Answer 2

I use Bowman to consume JSON+HAL resources in JAVA. This library greatly simplifies the consumption of resources comparing to RestTemplate as shown in this article.

Answer 3

I too faced a similar problem. And the way I chose to work around it is :

        ResponseEntity<String> response = restTemplate.exchange(
                "http://localhost:8080/payment/search/findByApprovalDate?approvalDate=2017-11-06", HttpMethod.GET,
                null, String.class);

        String data = response.getBody();

        ObjectMapper om = new ObjectMapper();
        om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        JsonNode jsNode = om.readTree(data);
        String test = jsNode.at("/_embedded/payment").toString();

        payments = om.readValue(test, new TypeReference<List<RHPayment>>() {
        });

Answer 4

Definitely, you should go with Traverson

Traverson client = new Traverson(new URI("http://localhost:8080/api/"), 
         MediaTypes.HAL_JSON);
    Resources<Resource<Teacher>> teachers = client
        .follow("school:teachers")
        .toObject(new ResourcesType<Resource<Teacher>>(){});

https://docs.spring.io/spring-hateoas/docs/current/reference/html/#client.traverson