public static String postDataWithCert(String url, String xmlObj, String mchId, String certPath) {
    // 加载证书
    try {
        initCert(mchId, certPath);
    } catch (Exception e) {
        e.printStackTrace();
    }
    String result = null;
    HttpPost httpPost = new HttpPost(url);
    // 得指明使用UTF-8编码，否则到API服务器XML的中文不能被成功识别
    StringEntity postEntity = new StringEntity(xmlObj, "UTF-8");
    httpPost.addHeader("Content-Type", "text/xml");
    httpPost.setEntity(postEntity);
    // 根据默认超时限制初始化requestConfig
    requestConfig = RequestConfig.custom().setSocketTimeout(socketTimeout).setConnectTimeout(connectTimeout).build();
    // 设置请求器的配置
    httpPost.setConfig(requestConfig);
    try {
        HttpResponse response = null;
        try {
            response = httpClient.execute(httpPost);
        } catch (IOException e) {
            e.printStackTrace();
        }
        HttpEntity entity = response.getEntity();
        try {
            result = EntityUtils.toString(entity, "UTF-8");
        } catch (IOException e) {
            e.printStackTrace();
        }
    } finally {
        httpPost.abort();
    }
    return result;
}