Ошибка 500 json

I am relatively new to Android and I am using JSON to get data from a server. On the first loop at line 22, the StringBuilder contains, 500 Internal Server Error and then the jArray ends up coming back null. How can I handle this error?

public static JSONObject getJSON() {
    String jsonString = "";
    InputStream inStream = null;

    //http post
    JSONObject jArray = null;
    try {
        HttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());
        HttpPost httpPost = new HttpPost(WS_URL);
        httpPost.setHeader("Content-type", "application/json");

        HttpResponse response = httpClient.execute(httpPost);
        HttpEntity entity = response.getEntity();
        inStream = entity.getContent();

        BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, "UTF-8"), 8);
        StringBuilder sb = new StringBuilder();

        String line = null;

        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        inStream.close();
        jsonString = sb.toString();

        jArray = new JSONObject(jsonString);


        //outputTransactions(jArray);

    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return jArray;
}

asked Feb 28, 2015 at 20:18

Though its a late reply but it might help others. You need to check the response status from the server before parsing it as JSON.

For ex.

int status_code=response.getStatusLine().getStatusCode();

if(status_code!=200){
    Log.d("MYLOG","ERROR! Response status is"+status_code);
  }
else{
    inStream = entity.getContent();
    BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, "UTF-8"), 8);
    StringBuilder sb = new StringBuilder();

    String line = null;

    while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
    }
    inStream.close();


   // Rest of your code......
    }

or Optionally you can check the status code and display the error to the user

Like:

else if(status_code==404){
 Log.d("MYLOG","Sorry! Page not found! Check the URL ");

}else if(status_code==500){
 Log.d("MYLOG","Server is not responding! Sorry try again later..");
}

Hope it helps for newbies like you

answered May 28, 2015 at 10:27

A «500 Internal Server» error means the server had a problem responding to your request. You are not getting a JSON string response.

Then when you try to create your jArray, the string is not valid JSON and the JSONObject cannot parse it — it returns «null» as you say.

You can parse the server response to see if it contains this string, and then create whatever jArray object you want, but you can’t get a JSON object from a non-JSON string.

answered Feb 28, 2015 at 20:39

You should consider use a library to handle the REST requests like: http://square.github.io/retrofit/

If you use a library like that you can get an object from json when a success response is available and other when an error occur.

    MyApi mylogin = restAdapter.create(MyApi.class); //this is how retrofit create your api
    mylogin.login(username,password,new Callback<String>() {
        @Override
        public void success(String s, Response response) {
            //process your response if login successfull you can call Intent and launch your main activity

        }

        @Override
        public void failure(RetrofitError retrofitError) {
            retrofitError.printStackTrace(); //to see if you have errors
        }
    });
    }

answered Feb 28, 2015 at 21:32

I got the same problem like you and I solved it because I missed a part while adding GSON .jar files to adding my serverside project. I think you should carrefully add external libraries to your project too like me.With these links I could aware of problem .

LINK 1

LINK 2

When ASP.NET MVC throws an exception, it returns a 500 error with response type text/html— which, of course, is invalid JSON.

I want to respond to an Ajax request expecting JSON with an error I can receive and display to the user.

1. Is it possible to return JSON with an HTTP status code of 500?

2. When the problem is a missing parameter, the 500 error occurs before the controller is even called — so a controller solution might not work. For example, leaving a required parameter out in a call to an Action that normally returns a JsonResult, ASP.NET MVC sends this back to the client:

Server Error in ‘/’ Application. The parameters dictionary contains a
null entry for parameter ‘id’ of non-nullable type ‘System.Int32’ for
method ‘System.Web.Mvc.JsonResult EditUser(Int32, System.String,
System.String, System.String, System.String, System.String,
System.String, System.String, System.String)’ in ‘bhh’. An optional
parameter must be a reference type, a nullable type, or be declared as
an optional parameter. Parameter name: parameters

I’m using jQuery; is there a better way to handle this?