public static String  sendGet2(String url) throws IOException {
            //实例化httpclient，（4.5新版本和以前不同），实例化方式有两种
            CloseableHttpClient httpClient = HttpClients.createDefault();
            HttpGet httpGet = new HttpGet(url);
            httpGet.setHeader("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:60.0) Gecko/20100101 Firefox/60.0");
            CloseableHttpResponse response = null;
            try {
                /**
                 * 底层http链接仍由响应对象保存
                 * 允许直接从网络套接字流式传输响应内容
                 * 为了确保正确释放系统资源
                 * 用户必须从finally子句中调用CloseableHttpResponse #close()
                 */
                response = httpClient.execute(httpGet);
                System.out.println(response.getStatusLine());
                HttpEntity entity = response.getEntity();
                //对响应主体做一些有用的事情
                //并确保他完全被消耗掉
                String s = EntityUtils.toString(entity, "utf-8");
                return s;
            } catch (IOException e) {
                e.printStackTrace();
                return e.toString();
            } finally {
                response.close();
            }
    }