Simple wrapper for Spring RestTemplate requests and object mapping.

RestUtils.class

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.http.*;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

import java.io.IOException;
import java.util.List;

/**
 * @author woemler
 */
public class RestUtils {

	public static boolean isError(HttpStatus status) {
		HttpStatus.Series series = status.series();
		return !status.equals(HttpStatus.NOT_FOUND) && (HttpStatus.Series.SERVER_ERROR.equals(series) || HttpStatus.Series.CLIENT_ERROR
				.equals(series));
	}

	public static HttpEntity<String> createRequest(){
		HttpHeaders headers = new HttpHeaders();
		headers.add("Accept", MediaType.APPLICATION_JSON_VALUE);
		return new HttpEntity<String>(headers);
	}
	
	public static RestTemplate getRestTemplate(){
		return new RestTemplate();
	}
	
	public static ObjectMapper getObjectMapper(){
		return new ObjectMapper();
	}

	public static <T> T fetchSingle(String url, Class<T> model, String id){
		HttpEntity<String> request = createRequest();
		ResponseEntity<String> response = getRestTemplate().exchange(
				url,
				HttpMethod.GET,
				request,
				String.class,
				id
		);
		try {
			if (RestUtils.isError(response.getStatusCode())) {
				RestError restError = getObjectMapper().readValue(response.getBody(), RestError.class);
				throw new RestClientException("[" + restError.getCode() + "] " + restError.getMessage());
			} else {
				return getObjectMapper().readValue(response.getBody(), model);
			}
		} catch (IOException e){
			throw new RuntimeException(e);
		}
	}

	public static <T> T fetchSingle(String url, Class<T> model, Object[] parameters){
		HttpEntity<String> request = createRequest();
		ResponseEntity<String> response = getRestTemplate().exchange(
				url,
				HttpMethod.GET,
				request,
				String.class,
				parameters
		);
		try {
			if (RestUtils.isError(response.getStatusCode())) {
				RestError restError = getObjectMapper().readValue(response.getBody(), RestError.class);
				throw new RestClientException("[" + restError.getCode() + "] " + restError.getMessage());
			} else {
				return getObjectMapper().readValue(response.getBody(), model);
			}
		} catch (IOException e){
			throw new RuntimeException(e);
		}
	}

	public static <T> List<T> fetchMultiple(String url, Class<T> model, Object[] parameters){
		HttpEntity<String> request = createRequest();
		ResponseEntity<String> response = getRestTemplate().exchange(
				url,
				HttpMethod.GET,
				request,
				String.class,
				parameters
		);
		try {
			if (RestUtils.isError(response.getStatusCode())) {
				RestError restError = getObjectMapper().readValue(response.getBody(), RestError.class);
				throw new RestClientException("[" + restError.getCode() + "] " + restError.getMessage());
			} else {
				return getObjectMapper().readValue(response.getBody(), getObjectMapper().getTypeFactory().constructCollectionType(List.class, model));

			}
		} catch (IOException e){
			throw new RuntimeException(e);
		}
	}

	public static <T> List<T> fetchMultiple(String url, Class<T> model){
		return fetchMultiple(url, model, new Object[]{});
	}

	public static class RestError {

		private HttpStatus status;
		private Integer code;
		private String message;
		private String developerMessage;
		private String moreInfoUrl;

		public RestError() { }

		public RestError(HttpStatus status, Integer code, String message, String developerMessage,
				String moreInfoUrl) {
			if (status == null){
				throw new NullPointerException("HttpStatus argument cannot be null.");
			}
			this.status = status;
			this.code = code;
			this.message = message;
			this.developerMessage = developerMessage;
			this.moreInfoUrl = moreInfoUrl;
		}

		public HttpStatus getStatus() {
			return status;
		}

		public Integer getCode() {
			return code;
		}

		public String getMessage() {
			return message;
		}

		public String getDeveloperMessage() {
			return developerMessage;
		}

		public String getMoreInfoUrl() {
			return moreInfoUrl;
		}

	}
	
}

Hello! I'm trying to consume an API, and found its wrapper class, the api I'm consuming has a complex JSON
https://bittrex.com/api/v1.1/public/getmarkets
so I have a model with generics ApiResult that has the attributes success, message and T result how to use your wrapper and for this Pojo?
ApiResult <List > apiResult

Robson C