android如何将POST json请求发送到Laravel Framework

Hi im doing both android and laravel framework.. but when i do post method and send json to laravel api via POST.. it will give a 500 result.. please help..

this is one of my asynctask in android sending the post data.. assume sendJsonObj is a jsonobject with values..

URL url = new URL("http://dexter-laravelframe.rhcloud.com/register");

        urlConnect = (HttpURLConnection) url.openConnection();
        urlConnect.setRequestMethod("POST");
        urlConnect.setConnectTimeout(10000);
        urlConnect.setRequestProperty("Content-Type", "application/json");
        urlConnect.setRequestProperty("x-csrf-token", Model_Application.token_csrf);
        urlConnect.connect();

        OutputStreamWriter outWrite = new OutputStreamWriter(urlConnect.getOutputStream());
        outWrite.write(sendJsonObj.toString());
        outWrite.flush();
        outWrite.close();

        int code = urlConnect.getResponseCode();`

on my Laravel framework.. routes.php Route::post('/register', 'UserController@register');

UserController.php

public function register()
{
    $json = Input::json()->all();

    $resultJson = json_encode($json);

    echo $resultJson;

}

this will give a 500 response code from Laravel api.. i want it to read the json data.. and send it back.. if i used Mozilla plugin rest client, and send the json data in body.. it gives 200..