android 中解析 json 字符串的问题， json 字符串是被压缩过的

private boolean isGZip = true;

        @Override
        public void run() {
            HttpURLConnection connection = null;
            try {
                URL url = new URL("http://wthrcdn.etouch.cn/weather_mini?city=芜湖");
                //URL url = new URL("http://www.weather.com.cn/data/list3/city.xml");
                connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod("GET");
                connection.setConnectTimeout(8000);
                connection.setReadTimeout(8000);
                String response = "";
                if (connection.getResponseCode() == 200) {// 判断请求码是否是200码，否则失败
                    InputStream is = connection.getInputStream(); // 获取输入流
                    System.out.println(connection.getContentEncoding());
                    if (isGZip ) {

                        //InflaterInputStream ilis = new InflaterInputStream(is);
                        GZIPInputStream in = new GZIPInputStream(is);
                        BufferedReader reader = new BufferedReader(
                                new InputStreamReader(in, "utf-8"));
                        String line = "";
                        while ((line = reader.readLine()) != null) {
                            response += line;
                        }
                    } else {
                        BufferedReader reader = new BufferedReader(
                                new InputStreamReader(is, "utf-8"));
                        String line = "";
                        while ((line = reader.readLine()) != null) {
                            response += line;
                        }
                    }
                }
                System.out.println(response);
            } catch (Exception e) {
            } finally {
                if (connection != null) {
                    connection.disconnect();
                }
            }
        }
    }).start();