public HttpResponse execute(HttpRequest request) throws IOException {
        final HttpURLConnection urlConn = createConnection(request);
        urlConn.connect();

        final HttpHeaders headers = new HttpHeaders(urlConn.getHeaderFields());
        final HttpRespStatus status = HttpRespStatus.valueOf(urlConn.getResponseCode());
        if (SUCCESS.contains(status.code())) {
            return new HttpResponse(status, headers, toBytes(urlConn.getInputStream()));
        } else {
            return new HttpResponse(status, headers, toBytes(urlConn.getErrorStream()));
        }
    }
@Test
    public void testGet() {
        HttpRequest req = new HttpRequest.Builder()
                .url("http://www.baidu.com")
//                .header("Connection", "close")
                .get()
                .build();
        try {
            HttpResponse resp = httpClient.execute(req);
            HttpHeaders headers = resp.getHeaders();
            System.out.println("Status=" + resp.getStatus());
            System.out.println("Connection=" + headers.get("Connection"));
            System.out.println(resp.getBodyString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }