public static String http(String url, Map<String, String> params) {

        // 构建请求参数
        String postData = "";
        if (params != null && params.size() > 0) {

            StringBuilder sb = new StringBuilder();
            for (Entry<String, String> e : params.entrySet()) {
                sb.append(e.getKey());
                sb.append("=");
                sb.append(e.getValue());
                sb.append("&");
            }
            postData = sb.toString().substring(0, sb.length() - 1);
        }

        System.out.println("send_url:" + url);
        System.out.println("send_data:" + postData);

        // 尝试发送请求
        HttpURLConnection con = null;
        try {
            con = (HttpURLConnection) new URL(url).openConnection();
            System.out.println(con.getConnectTimeout());
            con.setConnectTimeout(60000);
            System.out.println(con.getConnectTimeout());
            // con.setReadTimeout(30000);

            con.setRequestMethod("POST");
            con.setDoOutput(true);
            con.setDoInput(true);
            con.setUseCaches(false);
            con.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");

            // 写数据
            OutputStreamWriter osw = new OutputStreamWriter(
                    con.getOutputStream(), "UTF-8");
            osw.write(postData);
            osw.flush();
            osw.close();

            // 读取返回内容
            StringBuilder buffer = new StringBuilder();

            BufferedReader br = new BufferedReader(new InputStreamReader(
                    con.getInputStream(), "UTF-8"));
            String temp = null;
            while ((temp = br.readLine()) != null) {
                buffer.append(temp);
                buffer.append("\n");
            }
            return buffer.toString();
        } catch (Exception e) {

            e.printStackTrace();
            return "";

        } finally {
            if (con != null) {
                con.disconnect();
            }
        }

    }