public static final MediaType JSON = MediaType.get("application/json");

​

OkHttpClient client = new OkHttpClient();

​

String post(String url, String json) throws IOException {

  RequestBody body = RequestBody.create(json, JSON);

  Request request = new Request.Builder()

      .url(url)

      .post(body)

      .build();

  try (Response response = client.newCall(request).execute()) {

    return response.body().string();

  }

}