Java 字符串到 json 对象

Question

我正在尝试将 Json 与 android 一起使用我有一个 link returns 一个 Json 字符串

InputStream is = new URL(url).openStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
String jsonText = readAll(rd);
JSONObject json = new JSONObject(jsonText);

但是，在创建一个新的 JSONObject(jsonText) 时；它压碎了。

这是我的URL：http://igorsdomain.byethost3.com/getUser.php?username=SailorBoogy&password=qwerty&event=2222

这是返回的对象：{"ID":"23","Username":"SailorBoogy","Password":"qwerty","eventID":"6"}

我也试过 JSONObject(jsonText.replaceAll("\"" , "\\\"")); 但是没用。

有什么问题吗？我用错了吗？

Json 图书馆：

org.json.JSONException; org.json.JSONObject; org.json.JSONStringer;

Answer 1

没有 LogCat 很难说，但可能你正在 MainThread 上进行网络操作，而 Android 正在抱怨（因为它是一个阻塞操作，所以 UI 将通过抛出 android.os.NetworkOnMainThreadException 来冻结）。如果是这种情况，您可以通过在另一个线程中执行此操作来解决（例如，通过使用 AsyncTask 或外部库，例如 AndroidAsyncHttp）

Answer 2

首先让你的 json 在像 asynchronousTask 这样的网络线程中。

 DefaultHttpClient   httpclient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httppost = new HttpPost(http://someJSONUrl/jsonWebService);
// Depends on your web service
httppost.setHeader("Content-type", "application/json");

InputStream inputStream = null;
String result = null;
try {
HttpResponse response = httpclient.execute(httppost);           
HttpEntity entity = response.getEntity();

inputStream = entity.getContent();
// json is UTF-8 by default
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();

String line = null;
while ((line = reader.readLine()) != null)
{
    sb.append(line + "\n");
}
result = sb.toString();
} catch (Exception e) { 
// Oops
}
finally {
try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
}

然后像这样解析它

try {
        JSONObject jObject = new JSONObject(result);
        Log.d("username", jObject.getString("Username"));
        Toast.makeText(getApplicationContext(), jObject.getString("Username"), Toast.LENGTH_LONG).show();
        Log.d("Password", jObject.getString("Password"));
        Log.d("eventID", jObject.getString("eventID"));
    } catch (JSONException e) {
        e.printStackTrace();
    }

查看更多信息this

Answer 3

我强烈建议您使用 Volley、Loopj、Okhttp 等网络库进行网络操作。

这是您的问题的代码。

class LongOpreation extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... params) {

        String str = "";

        try {
            str = sendGetRequest();

        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return str;
    }

    public String sendGetRequest() throws MalformedURLException {
        StringBuilder response = new StringBuilder();
        String requrl = "";
        requrl = "http://igorsdomain.byethost3.com/getUser.php?username=SailorBoogy&password=qwerty&event=2222";
        response = requestExecuter(requrl);


        return response.toString();

    }


    @Override
    protected void onPostExecute(String result) {
        try {
            JSONObject jsonObject = new JSONObject(result);
            System.out.println("json-----------------------"+jsonObject);
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    @Override
    protected void onPreExecute() {

    }
    public StringBuilder requestExecuter(String str) {
        StringBuilder response = new StringBuilder();
        try {
            URL url = new URL(str);

            HttpURLConnection httpconn = (HttpURLConnection) url
                    .openConnection();
            httpconn.setConnectTimeout(5000);
            httpconn.setReadTimeout(10000);

            if (httpconn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                BufferedReader input = new BufferedReader(
                        new InputStreamReader(httpconn.getInputStream()));
                String strLine = null;
                while ((strLine = input.readLine()) != null) {
                    response.append(strLine);

                }
                input.close();
            }
            } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return response;
    }
}

简单调用new LongOperation().execute("");，你就完成了

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