Http连接getInputStream空指针异常android

Question

我在方法getInputStream（）上得到空指针异常，我知道urlConnection不为null

URL url = new URL(strUrl);

        /** Creating an http connection to communcate with url */
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

        /** Connecting to url */
        urlConnection.connect();

        /** Reading data from url */
        iStream = urlConnection.getInputStream();

Url字符串很好我在浏览器中查看它。 谢谢。