httpclient 直接json请求

已有json请求参数

        String url = "http://192.168.15.23:8180/ab_admin?action=policy_check";

        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);

        StringEntity entity = new StringEntity(param, "utf-8");//解决中文乱码问题
        entity.setContentEncoding("UTF-8");
        entity.setContentType("application/json");
        httpPost.setEntity(entity);
        CloseableHttpResponse response = httpclient.execute(httpPost);
        String respContent = "";
        if (response.getStatusLine().getStatusCode() == 200) {
            HttpEntity he = response.getEntity();
            respContent = EntityUtils.toString(he, "UTF-8");
            return respContent;
        }