Android - ошибка при получении JSON с url

Question

Я написал API для своего мобильного приложения. Он находится на http://tymonradzik.pl/THUNDER_HUNTER/thapi.php и возвращает данные в формате JSON. Я хотел написать метод входа, но когда мое приложение должно спросить API, я получаю сообщение об ошибке, и я не знаю, в чем причина этой ошибки.

Это часть моей функции входа:

public static String logIn(String nick, String password) 
    { 
     Log.e("2", "1"); //added by me to debug 
     JSONParser jParser = new JSONParser(); 
     Log.e("2", "2"); //added by me to debug 
     Log.wtf("Error !", "http://tymonradzik.pl/THUNDER_HUNTER/thapi.php?q=login&username=" + nick + "&password=" + password + "&imei="); 
     String json = jParser.getJSONFromUrl("http://tymonradzik.pl/THUNDER_HUNTER/thapi.php?q=login&username=" + nick + "&password=" + haslo + "&imei="); 
    Log.e("2", "3"); 
    Log.e("aaa",json.toString()); 
    JSONObject jObject; 
    try { 
     jObject = new JSONObject(json); //That is crash line ! 
     String error = jObject.getString("error"); 
     Log.e("ADSFDSFSDF", error); 
    } catch (JSONException e1) { 
     // TODO Auto-generated catch block 
     e1.printStackTrace(); 
    } 
    Log.e("2", "3"); 

Мой JSONParser класс:

package com.radzik.thunter; 


import java.io.BufferedReader; 

import java.io.InputStream; 
import java.io.InputStreamReader; 


import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 

import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.params.BasicHttpParams; 

import org.json.JSONObject; 



public class JSONParser { 

    static InputStream is = null; 
    static JSONObject jObj = null; 
    static String json = ""; 

    // constructor 
    public JSONParser() { 

    } 

    public String getJSONFromUrl(String url) { 

     DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams()); 
     HttpPost httppost = new HttpPost(url); 
     // 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){} 
     } 

     return result; 
    } 
} 

Мой LogCat:

07-24 13:11:08.440: E/2(18212): 1 
07-24 13:11:08.440: E/2(18212): 2 
07-24 13:11:08.440: A/Error !(18212): http://tymonradzik.pl/THUNDER_HUNTER/thapi.php?q=login&username=aaa&password=bbb&imei= 
07-24 13:11:08.475: D/AndroidRuntime(18212): Shutting down VM 
07-24 13:11:08.480: W/dalvikvm(18212): threadid=1: thread exiting with uncaught exception (group=0x414e92a0) 
07-24 13:11:08.485: E/AndroidRuntime(18212): FATAL EXCEPTION: main 
07-24 13:11:08.485: E/AndroidRuntime(18212): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.radzik.thunter/com.radzik.thunter.ThunderHunter}: java.lang.NullPointerException 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread.access$600(ActivityThread.java:140) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.os.Handler.dispatchMessage(Handler.java:99) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.os.Looper.loop(Looper.java:137) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread.main(ActivityThread.java:4898) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at java.lang.reflect.Method.invokeNative(Native Method) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at java.lang.reflect.Method.invoke(Method.java:511) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at dalvik.system.NativeStart.main(Native Method) 
07-24 13:11:08.485: E/AndroidRuntime(18212): Caused by: java.lang.NullPointerException 
07-24 13:11:08.485: E/AndroidRuntime(18212): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at org.json.JSONTokener.nextValue(JSONTokener.java:94) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at org.json.JSONObject.<init>(JSONObject.java:154) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at org.json.JSONObject.<init>(JSONObject.java:171) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at com.radzik.thunter.FunkcjeAPI.zalogujSie(FunkcjeAPI.java:20) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at com.radzik.thunter.ThunderHunter.onCreate(ThunderHunter.java:30) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.Activity.performCreate(Activity.java:5206) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083) 
07-24 13:11:08.485: E/AndroidRuntime(18212): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064) 
07-24 13:11:08.485: E/AndroidRuntime(18212): ... 11 more 

Я не знаю, в чем причина моей неудачи. Я добавил разрешение INTERNET в свой AndroidManifest.xml. Я звоню logIn функцию в моей основной деятельности так:

APIFunctions.logIn("aaa", "bbb"); 

NullPointerException используя Джеймс Holderness ответ

07-26 16:42:41.665: E/AndroidRuntime(345): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.radzik.thunter/com.radzik.thunter.ThunderHunter}: java.lang.NullPointerException: println needs a message 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread.access$600(ActivityThread.java:140) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.os.Handler.dispatchMessage(Handler.java:99) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.os.Looper.loop(Looper.java:137) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread.main(ActivityThread.java:4898) 
07-26 16:42:41.665: E/AndroidRuntime(345): at java.lang.reflect.Method.invokeNative(Native Method) 
07-26 16:42:41.665: E/AndroidRuntime(345): at java.lang.reflect.Method.invoke(Method.java:511) 
07-26 16:42:41.665: E/AndroidRuntime(345): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) 
07-26 16:42:41.665: E/AndroidRuntime(345): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) 
07-26 16:42:41.665: E/AndroidRuntime(345): at dalvik.system.NativeStart.main(Native Method) 
07-26 16:42:41.665: E/AndroidRuntime(345): Caused by: java.lang.NullPointerException: println needs a message 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.util.Log.println_native(Native Method) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.util.Log.e(Log.java:297) 
07-26 16:42:41.665: E/AndroidRuntime(345): at com.radzik.thunter.FunkcjeAPI.zalogujSie(FunkcjeAPI.java:19) 
07-26 16:42:41.665: E/AndroidRuntime(345): at com.radzik.thunter.ThunderHunter.onCreate(ThunderHunter.java:30) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.Activity.performCreate(Activity.java:5206) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083) 
07-26 16:42:41.665: E/AndroidRuntime(345): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064) 
07-26 16:42:41.665: E/AndroidRuntime(345): ... 11 more 

Answer 1

Client:

import com.google.gson.Gson; 

private static final String LOG = "Login layout"; 
private static final String URL = "xxx"; 

@SuppressWarnings("unused") 
@Override 
public void onClick(View view) { 
    Resources standardResources = getApplicationContext().getResources(); 
    AssetManager assets = standardResources.getAssets(); 
    DisplayMetrics metrics = standardResources.getDisplayMetrics(); 
    Configuration config = new Configuration(standardResources.getConfiguration()); 
    Resources defaultResources; 

    int id = view.getId(); 
    if (id == R.id.btnCheck) { 
     if (isNetworkAvailable()) { 
      try { 
       if (!login.getText().toString().equals("") 
         && !password.getText().toString().equals("")) { 
        HttpComunication task = new HttpComunication(); 
        task.login(login.getText().toString(), password 
          .getText().toString(), false); 
        task.execute(new String[] { URL }); 
        if (!task.get().equals("0")) { 
         Log.i(LOG, task.get()); 
         Profile profile = new Gson().fromJson(task.get(), 
           Profile.class); 

         Intent intent = new Intent(getApplicationContext(), 
           StopPointsActivity.class); 
         intent.putExtra("PROFILE", profile); 
         intent.putExtra("LOGIN", login.getText().toString()); 
         intent.putExtra("PASS", password.getText() 
           .toString()); 

         startActivity(intent); 
         finish(); 
        } else { 
         Toast.makeText(
           getApplicationContext(), 
           getResources().getString(
             R.string.incorect_data), 
           Toast.LENGTH_LONG).show(); 
        } 
       } else { 
        Toast.makeText(getApplicationContext(), 
          getResources().getString(R.string.empty_data), 
          Toast.LENGTH_LONG).show(); 
       } 

      } catch (Exception e) { 
       Log.e(LOG, e.toString()); 
      } 
     } else { 
      Toast.makeText(getApplicationContext(), 
        getResources().getString(R.string.error_connection), 
        Toast.LENGTH_LONG).show(); 
     } 
    } 
} 

private boolean isNetworkAvailable() { 
    ConnectivityManager connectivityManager 
      = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo(); 
    return activeNetworkInfo != null && activeNetworkInfo.isConnected(); 
} 
} 



public class HttpComunication extends AsyncTask<String, Void, String> { 
private String login; 
private String password; 
private boolean isLoged; 
private String logReport; 
private String start; 
private String stop; 

public void login(String _login, String _password, boolean _isLoged) { 
    this.login = _login; 
    this.password = _password; 

    if (_isLoged) { 
     logReport = "yes"; 
    } else { 
     logReport = "no"; 
    } 
    this.isLoged = _isLoged; 
} 

public void getPath(String _start, String _stop) { 
    this.start = _start; 
    this.stop = _stop; 
} 

@Override 
protected String doInBackground(String... urls) { 
    String output = null; 
    if (!isLoged) { 
     for (String url : urls) { 
      output = loginToSystem(url); 
     } 
    } else { 
     for (String url : urls) { 
      output = getSchedules(url); 
     } 
    } 
    return output; 
} 

private String loginToSystem(String url) { 
    String output = null; 
    try { 
     DefaultHttpClient httpClient = new DefaultHttpClient(); 
     HttpPost httpPost = new HttpPost(url); 

     ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>(); 
     postParameters.add(new BasicNameValuePair("username", login)); 
     postParameters.add(new BasicNameValuePair("password", password)); 
     postParameters.add(new BasicNameValuePair("loged", logReport)); 
     httpPost.setEntity(new UrlEncodedFormEntity(postParameters)); 

     HttpResponse httpResponse = httpClient.execute(httpPost); 
     HttpEntity httpEntity = httpResponse.getEntity(); 
     output = EntityUtils.toString(httpEntity); 
    } catch (UnsupportedEncodingException e) { 
     e.printStackTrace(); 
    } catch (ClientProtocolException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return output; 
} 

private String getSchedules(String url) { 
    String output = null; 
    try { 
     DefaultHttpClient httpClient = new DefaultHttpClient(); 
     HttpPost httpPost = new HttpPost(url); 

     ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>(); 

     postParameters.add(new BasicNameValuePair("username", login)); 
     postParameters.add(new BasicNameValuePair("password", password)); 
     postParameters.add(new BasicNameValuePair("loged", logReport)); 
     postParameters.add(new BasicNameValuePair("start", start)); 
     postParameters.add(new BasicNameValuePair("stop", stop)); 
     httpPost.setEntity(new UrlEncodedFormEntity(postParameters)); 

     HttpResponse httpResponse = httpClient.execute(httpPost); 
     HttpEntity httpEntity = httpResponse.getEntity(); 
     output = EntityUtils.toString(httpEntity); 
    } catch (UnsupportedEncodingException e) { 
     e.printStackTrace(); 
    } catch (ClientProtocolException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return output; 
} 

@Override 
protected void onPostExecute(String output) { 
} 

}

Серуэр:

protected void service(HttpServletRequest req, HttpServletResponse resp) 
     throws ServletException, IOException { 
    Profile result; 
    String userName, password, start, stop; 

    if (req.getParameter("loged").equals("no")) { 

     userName = req.getParameter("username"); 
     password = req.getParameter("password"); 

     if (CheckData.comfirmData(userName, password)) { 
      result = CheckData.getProfile(userName, password); 
      String finalJSON = new Gson().toJson(result); 
      resp.setContentType("application/json"); 
      resp.setCharacterEncoding("UTF-8"); 
      resp.getWriter().print(finalJSON); 
     } else { 
      resp.getWriter().print(0); 
     } 
    } else if (req.getParameter("loged").equals("yes")) { 

     userName = req.getParameter("username"); 
     password = req.getParameter("password"); 

     if (CheckData.comfirmData(userName, password)) { 
      start = req.getParameter("start"); 
      stop = req.getParameter("stop"); 
      resp.getWriter().print("Mam zgloszenie o " + start + " -> " + stop); 
     } else { 
      resp.getWriter().print(0); 
     } 
    } else { 
     resp.getWriter().print(0); 
    } 
} 

проверки:

private static String localLogin = "Dragy"; 
private static String localPassword = "qwe"; 
    protected static boolean comfirmData(String userName, String password) { 
    if (userName.equals(localLogin) && password.equals(localPassword)) { 
     fillDataForUser(); 
     return true; 
    } else { 
     return false; 
    } 
} 

Answer 2

Она смотрит на меня, как вы посылаете запрос POST на сервер, который ожидает в GET. Кроме того, ваш запрос POST устанавливает заголовок Content-Type, но вы фактически не предоставили никакого контента.

Я ожидаю, что это приведет к сбою запроса, что приведет к исключению (которое вы игнорируете). Это означает результат , который возвращается с . GetJSONFromUrl имеет значение null, что в конечном итоге вызывает исключение нулевого указателя в парсере JSON.

Кроме того, почему вы переопределяете параметры HTTP по умолчанию пустым BasicHttpParams? Если вы оставите этот параметр, клиент будет инициализирован параметрами HTTP по умолчанию, которые выглядят как более разумный вариант.

Вы можете преобразовать ваш запрос POST на запрос GET, и избавиться от BasicHttpParams, заменив первые несколько строк из getJSONFromUrl так:

DefaultHttpClient httpclient = new DefaultHttpClient(); 
HttpGet httpget = new HttpGet(url); 

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

... 

Если это не работает , добавьте некоторые записи в обработчик исключений, чтобы узнать, что вызывает запрос.