Spring 4 REST Client example - RestTemplate

Spring 4 REST Client example - RestTemplate

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
headers.add(ProcessEngineConstants.AUTHOURIZED_USERNAME, username);
HttpEntity<Object> requestEntity = new HttpEntity<Object>("request_headers", headers);

Map<String, Object> restParams = new HashMap<>();
restParams.put("business_key", "123");
        
try {
    ParameterizedTypeReference<anObject> responseType = new ParameterizedTypeReference<anObject>() {};
    ResponseEntity<List<NodeDto>> results = restTemplate.exchange("http://localhost:8080/restService/callMe", HttpMethod.GET, requestEntity, responseType, restParams);
    if (results.getStatusCode().is4xxClientError() || results.getStatusCode().is5xxServerError()) {
        throw new HttpClientErrorException(results.getStatusCode());
    }
    return results.getBody();
} catch (HttpClientErrorException e) {
    throw new ProperCheckedException(e.getMessage(), e.getStatusCode());
}