getting data from external webservice

To access external webservice, you can use Zend HTTP Client class, using the below code:

protected $_httpClientFactory;

public function __construct(
    \Magento\Framework\HTTP\ZendClientFactory $httpClientFactory
) {
    $this->_httpClientFactory   = $httpClientFactory;
}

/**
 * Function to create CURL Request to External Server
 */
public function connect()
{
        $data['parameter1'] = 1;

        $client = $this->_httpClientFactory->create();
        $client->setUri($url);
        $client->getUri()->setPort($port);
        $client->setConfig(['timeout' => 300]);
        $client->setHeaders(['Content-Type: application/json', 'Accept: application/json']);
        $client->setMethod(\Zend_Http_Client::POST);
        $client->setRawData(json_encode($data));

        try {
            $responseBody = $client->request()->getBody();

            echo '<pre>';
            print_r($responseBody);
            die;
        } catch (\Exception $e) {
            echo $e->getMessage();
        }
    }
}