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;
}
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 :-)
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.
Take a look at this answer: https://stackoverflow.com/a/8148785/1974614
You should check the statusCode against 500
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
}
});
}
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
Related
I am using HttpClient 4.3.6 to perform http GET and POST requests. Right now I am using multipartentity to send a few string parameters and an image in the form of a file. I am able to successfully post the data but my problem comes in when I get the HTTP response. The response contains json data.
What happens is the HTTP response is incomplete and when i try to create a json object with the data i get jsonexception error saying:
Unterminated object at character 407.
I noticed that the response does not contain closed braces. Is this a problem on android or should I check the server? Because I am able to see the data properly on postman and on ios. I have never faced this issue before and don't know how to solve this.
This is my code to post and get the response:
#Override
protected String doInBackground(String... params) {
try {
String url = params[0];
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
MultipartEntity entity = new MultipartEntity();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
ByteArrayBody bab = new ByteArrayBody(imageBytes, "image.jpg");
entity.addPart("image_data", bab);
entity.addPart("action", new StringBody("1", "text/plain", Charset.forName("UTF-8")));
entity.addPart("name", new StringBody("asdfg", "text/plain", Charset.forName("UTF-8")));
entity.addPart("user_id", new StringBody("157", "text/plain", Charset.forName("UTF-8")));
entity.addPart("birthday", new StringBody("18-04-1995", "text/plain", Charset.forName("UTF-8")));
entity.addPart("gender", new StringBody("male", "text/plain", Charset.forName("UTF-8")));
entity.addPart("is_jlpt_student", new StringBody(String.valueOf(0), "text/plain", Charset.forName("UTF-8")));
entity.addPart("relationship", new StringBody("Father", "text/plain", Charset.forName("UTF-8")));
entity.addPart("relationship_id", new StringBody(String.valueOf(10002), "text/plain", Charset.forName("UTF-8")));
entity.addPart("is_creator", new StringBody(String.valueOf(1), "text/plain", Charset.forName("UTF-8")));
entity.addPart("email", new StringBody(email, "text/plain", Charset.forName("UTF-8")));
httppost.setEntity(entity);
HttpResponse resp = httpclient.execute(httppost);
String response = EntityUtils.toString(resp.getEntity());
Log.i("HttpResponse", response);
return response;
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute (String result) {
super.onPostExecute(result);
JSONObject jsonObject = null;
try {
jsonObject = new JSONObject(result);
JSONObject json_data = jsonObject.getJSONObject("data");
String json_userid = json_data.getString("user_id");
String json_username = json_data.getString("name");
String json_email = json_data.getString("email");
String json_country = json_data.getString("country_code");
String json_imagefilename = json_data.getString("image_filename");
String json_imgurl = json_data.getString("image_url");
Toast.makeText(ParentGuardianProfile.this, "ImageFile " + json_imagefilename, Toast.LENGTH_SHORT).show();
User new_user = userdao.createUser(json_userid, json_username, json_email,json_imagefilename,json_country,selectedImageUri.toString(), 1);
Log.i("SQLITE", "added user : " + new_user.getmUserName() + new_user.getmId());
} catch (JSONException e) {
e.printStackTrace();
}
}
And my json response is :
{"status":1,"message":"success","data":{"child_id":"381","name":"asdfg","image_filename":"C201603021734476.jpg","image_url":"https:\/\/innokid.blob.core.windows.net\/media\/child\/381.jpg","birthday":"18-04-1995","gender":"male","is_jltp_student":"0","relationship":"Father","relationship_id":"10002","is_creator":1,"rank":1,"qrcode_url":"http:\/\/innokid.azurewebsites.net\/uploads\/qrcode\/child_381.png"
I tried using String buffer as suggested in this post String is being truncated when its too long . But i still get the same result.
Code looks ok at first glance.
How do you got know that the json data is cut? Logcat can truncate text. Debugger should be more reliable in this case.
Try to generate this same request with some tools like curl / SoapUI and validate JSON you got with some formatter / validator (you'll easily find a few of such tools).
It's beyond the range of question, but using raw Android built-in communication libraries seems to be a little bit masochistic. Have you ever consider to use Retrofit?
I think this code is problematic String response = EntityUtils.toString(resp.getEntity());
may be you should use some other function to convert response toString...
Apparently the json is missing two curly brackets '}}' at the end, which can happen due to some bug in the toString code.
I pulled up an old project that was using the org.apache.http stuff and below is how I was parsing the response. As you can see it is rather cumbersome. There are many tested and maintained libraries out there that are better suited to this kind of heavy-lifting.
// Get hold of the response entity (-> the data):
HttpEntity entity = response.getEntity();
if (entity != null) {
// Read the content stream
InputStream instream = entity.getContent();
Header contentEncoding = response.getFirstHeader("Content-Encoding");
if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {
instream = new GZIPInputStream(instream);
}
// Convert content stream to a String
resultString = convertStreamToString(instream);
instream.close();
// Do stuff with resultString here
// Consume Content
entity.consumeContent();
}
And the convertStreamToString() method:
private static String convertStreamToString(InputStream is) {
/*
* To convert the InputStream to String we use the
* BufferedReader.readLine() method. We iterate until the BufferedReader
* return null which means there's no more data to read. Each line will
* appended to a StringBuilder and returned as String.
*
* (c) public domain:
* http://senior.ceng.metu.edu.tr/2009/praeda/2009/01/
* 11/a-simple-restful-client-at-android/
*/
BufferedReader reader = new BufferedReader(new InputStreamReader(is), 8192);
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
I finally solved this issue by replacing httpclient library with Android Asynchronous Http Client. Now it works fine. Thanks a lot for your help!
However, I still dont understand why the response was truncated when i used httpclient.
I create android apps as client and node as server, i got problem when i request value from android to node, i use this code in android to communicate with node js
String xResult = getRequestJSON("http://mydomain.com:8888");
public String getRequestJSON(String Url){
String sret="";
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(Url);
try{
HttpResponse response = client.execute(request);
sret =requestJSON(response);
}catch(Exception ex){
}
return sret;
}
public static String requestJSON(HttpResponse response){
String result = "";
try{
InputStream in = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder str = new StringBuilder();
String line = null;
while((line = reader.readLine()) != null){
str.append(line + "\n");
}
in.close();
result = str.toString();
}catch(Exception ex){
result = "Error";
}
return result;
}
and i got result like this in node.
[{"posid":"P0S6f50b314b2c279a2083cb0ef821ccb4d20140218120720","id_a":"ltv#ltv.com","gambar_a":"6f50b314b2c279a2083cb0ef821ccb4d.jpg","user":"lutfi soe","pwaktu":"2014-02-18T05:07:20.000Z","posnya":"test dr android","plat":-7.983757710988161,"plong":112.6549243927002,"pjenis":"I","vote":0}]
my question is,how i receive json like that in android ?and parse to string?
thanks
If you are receiving Json string in proper format then you can use JSON jar to parse this json.
You can get a tutorial for JSON parsing here
I think your question is more on how to parse and access the result in java[read Android].
Here is a solution that could help JavaScript type arrays in JAVA
JsonArray yourArray = new JsonParser()
.parse("[[\"2012-14-03\", 2]]")
.getAsJsonArray();
// Access your array like so - yourArray.get(0).getAsString();
// yourArray.get(0).getAsInt() etc
The above is using a library called Gson
P.S: I just plagiarized my own answer. Not sure what criteria to use to mark this question as a duplicate
Im doing a simple http get,
I see on my result an incomplete response,
what Im doing wrong?
here the code:
class GetDocuments extends AsyncTask<URL, Void, Void> {
#Override
protected Void doInBackground(URL... urls) {
Log.d("mensa", "bajando");
//place proper url
connect(urls);
return null;
}
public static void connect(URL[] urls)
{
HttpClient httpclient = new DefaultHttpClient();
// Prepare a request object
HttpGet httpget = new HttpGet("http://tiks.document.dev.chocolatecoded.com.au/documents/api/get?type=tree");
// Execute the request
HttpResponse response;
try {
response = httpclient.execute(httpget);
// Examine the response status
Log.d("mensa",response.getStatusLine().toString());
// Get hold of the response entity
HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to worry about connection release
if (entity != null) {
// A Simple JSON Response Read
InputStream instream = entity.getContent();
String result= convertStreamToString(instream);
// now you have the string representation of the HTML request
Log.d("mensa", "estratagema :: "+result);
JSONObject jObject = new JSONObject(result);
Log.d("mensa", "resposta jObject::"+jObject);
Log.d("mensa", "alive 1");
JSONArray contacts = null;
contacts = jObject.getJSONArray("success");
Log.d("mensa", "resposta jObject::"+contacts);
Log.d("mensa", "alive");
//instream.close();
}
} catch (Exception e) {}
}
private static String convertStreamToString(InputStream is) {
/*
* To convert the InputStream to String we use the BufferedReader.readLine()
* method. We iterate until the BufferedReader return null which means
* there's no more data to read. Each line will appended to a StringBuilder
* and returned as String.
*/
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
Log.d("mensa", "linea ::"+line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
i call it with:
GetDocuments get = new GetDocuments();
URL url = null;
try {
url = new URL("ftp://mirror.csclub.uwaterloo.ca/index.html");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//URL url = new URL("http://www.google.es");
get.execute(url);
edit 1
I refer to incomplete as the response that gets truncated?
please notice in below image of response how string gets truncated,
is this because of the log size?,
but the other problem is that it doesn't parse?
thanks!
I don't know if this is going to resolve your problem but you can get rid of your method and use simply:
String responseString = EntityUtils.toString(response.getEntity());
I've had exactly the same issue for the last couple of days. I found that my code worked over WiFi but not 3G. In other words I eliminated all the usual threading candidates. I also found that when I ran the code in the debugger and just waited for (say) 10 seconds after client.execute(...) it worked.
My guess is that
response = httpclient.execute(httpget);
is an asynchronous call in itself and when it's slow returns a partial result... hence JSON deserialization goes wrong.
Instead I tried this version of execute with a callback...
try {
BasicResponseHandler responseHandler = new BasicResponseHandler();
String json = httpclient.execute(httpget, responseHandler);
} finally {
httpclient.close();
}
And suddenly it all works. If you don't want a string, or want your own code then have a look at the ResponseHandler interface. Hope that helps.
I have confirmed that this is because size limit of java string. I have checked this by adding the string "abcd" with the ressponse and printed the response string in logcat. But the result is the truncated respose without added string "abcd".
That is
try {
BasicResponseHandler responseHandler = new BasicResponseHandler();
String json = httpclient.execute(httpget, responseHandler);
json= json+"abcd";
Log.d("Json ResponseString", json);
} finally {
httpclient.close();
}
So I put an arrayString to collect the response. To make array, I splitted My json format response by using "}"
The code is given below(This is a work around only)
BasicResponseHandler responseHandler = new BasicResponseHandler();
String[] array=client.execute(request, responseHandler).split("}");
Then you can parse each objects in to a json object and json array with your custom classes.
If you get any other good method to store response, pls share because i am creating custom method for every different json responses );.
Thank you
Arshad
Hi Now I am using Gson library to handle the responses.
http://www.javacodegeeks.com/2011/01/android-json-parsing-gson-tutorial.html
Thanks
Arshad
I cant' comment directly due to reputation, but in response to https://stackoverflow.com/a/23247290/4830567 I felt I should point out that the size limit of a Java String is about 2GB (Integer.MAX_VALUE) so this wasn't the cause of the truncation here.
According to https://groups.google.com/d/msg/android-developers/g4YkmrFST6A/z8K3vSdgwEkJ it is logcat that has a size limit, which is why appending "abcd" and printing in logcat didn't work. The String itself would have had the appended characters. The previously linked discussion also mentioned that size limits with the HTTP protocol itself can occasionally be a factor, but that most servers and clients handle this constraint internally so as to not expose it to the user.
I make a GET request to a server using HttpUrlConnection.
After connecting:
I get response code: 200
I get response message: OK
I get input stream, no exception thrown but:
in a standalone program I get the body of the response, as expected:
{"name":"my name","birthday":"01/01/1970","id":"100002215110084"}
in a android activity, the stream is empty (available() == 0), and thus I can't get
any text out.
Any hint or trail to follow? Thanks.
EDIT: here it is the code
Please note: I use import java.net.HttpURLConnection; This is the standard
http Java library. I don't want to use any other external library. In fact
I did have problems in android using the library httpclient from apache (some of their anonymous .class can't be used by the apk compiler).
Well, the code:
URLConnection theConnection;
theConnection = new URL("www.example.com?query=value").openConnection();
theConnection.setRequestProperty("Accept-Charset", "UTF-8");
HttpURLConnection httpConn = (HttpURLConnection) theConnection;
int responseCode = httpConn.getResponseCode();
String responseMessage = httpConn.getResponseMessage();
InputStream is = null;
if (responseCode >= 400) {
is = httpConn.getErrorStream();
} else {
is = httpConn.getInputStream();
}
String resp = responseCode + "\n" + responseMessage + "\n>" + Util.streamToString(is) + "<\n";
return resp;
I see:
200
OK
the body of the response
but only
200
OK
in android
Trying the code of Tomislav I've got the answer.
My function streamToString() used .available() to sense if there is any data received,
and it returns 0 in Android. Surely, I called it too soon.
If I rather use readLine():
class Util {
public static String streamToString(InputStream is) throws IOException {
StringBuilder sb = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
while ((line = rd.readLine()) != null) {
sb.append(line);
}
return sb.toString();
}
}
then, it waits for the data to arrive.
Thanks.
You can try with this code that will return response in String:
public String ReadHttpResponse(String url){
StringBuilder sb= new StringBuilder();
HttpClient client= new DefaultHttpClient();
HttpGet httpget = new HttpGet(url);
try {
HttpResponse response = client.execute(httpget);
StatusLine sl = response.getStatusLine();
int sc = sl.getStatusCode();
if (sc==200)
{
HttpEntity ent = response.getEntity();
InputStream inpst = ent.getContent();
BufferedReader rd= new BufferedReader(new InputStreamReader(inpst));
String line;
while ((line=rd.readLine())!=null)
{
sb.append(line);
}
}
else
{
Log.e("log_tag","I didn't get the response!");
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
The Stream data may not be ready, so you should check in a loop that the data in the stream is available before attempting to access it.
Once the data is ready, you should read it and store in another place like a byte array; a binary stream object is a nice choice to read data as a byte array. The reason that a byte array is a better choice is because the data may be binary data like an image file, etc.
InputStream is = httpConnection.getInputStream();
byte[] bytes = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] temp = new byte[is.available()];
while (is.read(temp, 0, temp.length) != -1) {
baos.write(temp);
temp = new byte[is.available()];
}
bytes = baos.toByteArray();
In the above code, bytes is the response as byte array. You can convert it to string if it is text data, for example data as utf-8 encoded text:
String text = new String(bytes, Charset.forName("utf-8"));
What's the easiest way to retrieve JSON from a web-service and to parse it? Without using any additional plug-ins?
This is the best way to retreive JSON data and parsing it, i have used it in my project and it works totally well. Check out this Tutorial (source code also available).
If you are using JSON, you will definitely need Google gson library to convert Java Objects into their JSON representation. You can download it from here.
If you want the standard procedure then you need to use JSONObject and JSONArray to parse responses. However, it is fuzzy and cumbersome when your response string contains a complex structure. In order to deal such complex responses its better to off the parsing to Gson, Jackson or any other library.
You should have a look here: http://code.google.com/p/android-query/wiki/AsyncAPI
Everything is explained, with the code samples you need.
The code below should give you a starting point, just use it in an activity/service class. Its gets data from a URL (webservice), and converts it into a JSON object you can use.
StringBuilder stringBuilder = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(***Put your web service URL here ***)
try
{
HttpResponse response = client.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200)
{
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null)
{
stringBuilder.append(line);
}
}
}
catch (ClientProtocolException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
//Turn string JSON into object you can process
JSONArray jsonArray = new JSONArray(stringBuilder.toString());
for (int i = 0; i < jsonArray.length(); i++)
{
//Get Each element
JSONObject jsonObject = jsonArray.getJSONObject(i);
//Do stuff
}