Question

我一直试图从API响应中获取JSONArray。 JSON响应完全有效，我在jsonlint.com上检查了相同的内容。但是当我调用并尝试处理它时，jsonarray返回为空。以下是通过浏览器尝试的API响应：{"IsBlockUser":"0","BlockedByUserId":"","BlockedMessage":"","ChatHistory":[{"UserName":"Ashish Bahl","UserId":"5475","UserImage":"9f0ecf01-7806-4fb4-b814-8ed81f7ff4ea.jpeg","Message":"bancho","ChatReciverType":"User","RecieverId":"4099","CreatedDate":"3/31/2017 11:47:58 AM","PrettyDate":"21 minutes ago"}]}

以下是用于进行API调用的代码：

`public static class PersonalChatTask extends AsyncTask<Void, Void, Void> {
        private static final String LOG_TAG = PersonalChatTask.class.getSimpleName();

    public PersonalChatTask() {
        super();
    }

    @Override
    protected Void doInBackground(Void... voids) {
        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;
        //Will contain the response as a raw JSON string.

        String dataString = null;

        try {
            //Here we construct the url for the movie database query
            //http://api.themoviedb.org/3/movie?

            //final String QUERY_PARAM = "sort_by";// sorting parameter popularity or rating

            Uri builtUri = Uri.parse(BuildConfig.BASE_URL).buildUpon()
                    .appendPath("Chat_GetChatHistory")
                    //.appendQueryParameter(QUERY_PARAM,params[0]) //String key , String value
                    .appendQueryParameter(TOKEN,getUserData().getToken())
                    .appendQueryParameter(API_KEY,BuildConfig.API_KEY_VALUE)
                    .appendQueryParameter("RecieverId","4099")
                    .appendQueryParameter("pageNumber","1")
                    .build();
            URL url = new URL(builtUri.toString());

            // Create the request to TheMovieDatabase, and open the connection
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();

            //read the input stream into a string
            InputStream inputStream = urlConnection.getInputStream();
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                //Do Nothing
                return null;
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null) {
                // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                // But it does make debugging a *lot* easier if you print out the completed
                // buffer for debugging.
                buffer.append(line);
            }

            if (buffer.length() == 0) {
                //Stream was empty.No point in parsing.
                return null;
            }
            dataString = buffer.toString();
            getDataFromJSONString(dataString);
        } catch (IOException e){
            // If the code didn't successfully get the weather data, there's no point in attemping
            // to parse it.
            Log.e(LOG_TAG, "Error ", e);
        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
            e.printStackTrace();
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (final IOException e) {
                    Log.e(LOG_TAG, "Error closing stream", e);
                }
            }

        }
        return null;
    }

    private void getDataFromJSONString(String dataString) throws JSONException {
        final String DB_CHAT_HISTORY = "ChatHistory";

        try {
            JSONObject chatJson = new JSONObject(dataString);
            JSONArray chatArray = chatJson.getJSONArray(DB_CHAT_HISTORY);

            int size = chatArray.length();

        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
            e.printStackTrace();
        }
    }
}`

我使用调试器检查变量 dataString ，这是{"IsBlockUser":"0","BlockedByUserId":"","BlockedMessage":"","ChatHistory":[]}

Answer 1

如果您确定要获得有效（非空）阵列，可以尝试其他方法......

ObjectMapper mapper = new ObjectMapper();
JsonNode arrayItems = mapper.readTree(dataString).get("DB_CHAT_HISTORY");

JsonArray chatArray = new JsonArray();
for (JsonNode chat : arrayItems)
    chatArray.add(chat);

无法解析来自服务器的JSON响应，获取空JSONArray

1 个答案: