code: private static void close(CloseableHttpClient httpClient, CloseableHttpResponse response) {
          try {
              if (response != null) {
                  response.close();
              }
              if (httpClient != null) {
                  httpClient.close();
              }
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
docs: 关闭连接,释放资源
  @param httpClient CloseableHttpClient
  @param response CloseableHttpResponse