Sending and Parsing JSON Objects in Android

Question

I would like to send messages in the form of JSON objects to a server and parse the JSON response from the server   Example of JSON object       post          username    John Doe        message    test message        image    image url        time     current time          I am trying to parse the JSON manually by going attribute by attribute  Is there any library utility I can use to make this process easier

User · Answer

if your are looking for fast json parsing in android than i suggest you a tool which is freely available.

JSON Class Creator tool

It's free to use and it's create your all json parsing class within a one-two seconds.. :D

User · Answer

You can use org json JSONObject and org json JSONTokener  you don t need any external libraries since these classes come with Android SDK

User · Answer

There s not really anything to JSON   Curly brackets are for  objects   associative arrays  and square brackets are for arrays without keys  numerically indexed    As far as working with it in Android  there are ready made classes for that included in the sdk  no download required    Check out these classes  http   developer android com reference org json package-summary html

User · Answer

GSON is easiest to use and the way to go if the data have a definite structure   Download gson   Add it to the referenced libraries   package com tut JSON   import org json JSONException  import org json JSONObject   import android app Activity  import android os Bundle  import android util Log   import com google gson Gson  import com google gson GsonBuilder   public class SimpleJson extends Activity           Called when the activity is first created          Override     public void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout main            String jString       username      tom      message      roger that                  GsonBuilder gsonb   new GsonBuilder            Gson gson   gsonb create            Post pst           try               pst   gson fromJson jString   Post class              catch  JSONException e                e printStackTrace                        Code for Post class  package com tut JSON   public class Post        String message      String time      String username      Bitmap icon

User · Answer

Other answers have noted Jackson and GSON - the popular add-on JSON libraries for Android  and json org  the bare-bones JSON package that is included in Android   But I think it is also worth noting that Android now has its own full featured JSON API   This was added in Honeycomb  API level 11   This comprises - android util JsonReader  docs  and source - android util JsonWriter  docs  and source  I will also add one additional consideration that pushes me back towards Jackson and GSON  I have found it useful to use 3rd party libraries rather then android   packages because then the code I write can be shared between client and server   This is particularly relevant for something like JSON  where you might want to serialize data to JSON on one end for sending to the other end   For use cases like that  if you use Java on both ends it helps to avoid introducing android   dependencies   Or I guess one could grab the relevant android   source code and add it to your server project  but I haven t tried that

User · Answer

This is the JsonParser class  public class JSONParser        static InputStream is   null      static JSONObject jObj   null      static String json               constructor     public JSONParser                 public JSONObject getJSONFromUrl String url                Making HTTP request         try                  defaultHttpClient             DefaultHttpClient httpClient   new DefaultHttpClient                HttpPost httpPost   new HttpPost url                HttpResponse httpResponse   httpClient execute httpPost               HttpEntity httpEntity   httpResponse getEntity                is   httpEntity getContent               catch  UnsupportedEncodingException e                e printStackTrace              catch  ClientProtocolException e                e printStackTrace              catch  IOException e                e printStackTrace                       try               BufferedReader reader   new BufferedReader new InputStreamReader                      is   iso-8859-1    8               StringBuilder sb   new StringBuilder                String line   null              while   line   reader readLine       null                    sb append line     n                              is close                json   sb toString              catch  Exception e                Log e  Buffer Error    Error converting result     e toString                           try parse the string to a JSON object         try               jObj   new JSONObject json             catch  JSONException e                Log e  JSON Parser    Error parsing data     e toString                           return JSON String         return jObj           Note  DefaultHttpClient is no longer supported by sdk 23  so it is advisable to use target sdk 21 with this code

User · Answer

You can download a library from http   json org  Json-lib or org json  and use it to parse generate the JSON

User · Answer

There are different open source libraries  which you can use for parsing json    org json  - If you want to read or write json then you can use this library  First create JsonObject  -  JSONObject jsonObj   new JSONObject  lt jsonStr gt      Now  use this object to get your values  -  String id   jsonObj getString  id      You can see complete example here  Jackson databind  - If you want to bind and parse your json to particular POJO class  then you can use jackson-databind library  this will bind your json to POJO class  -  ObjectMapper mapper   new ObjectMapper    post  mapper readValue json  Post class     You can see complete example here

User · Answer

you just need to import this     import org json JSONObject      constructing the String that you want to send   JSONObject param new JSONObject     JSONObject post new JSONObject      im using two object because you can have an jsonObject within another   post put  username here i write the key    someusername  here i put the value   post put  message   this is a sweet message    post put  image   http   localhost someimage jpg    post put  time     present time      then i put the post json inside another like this    param put  post  post     this is the method that i use to make a request    makeRequest param toString      public JSONObject makeRequest String param        try         setting the connection           urlConnection   new URL  your url            connection    HttpURLConnection  urlConnection openConnection            connection setDoOutput true           connection setRequestMethod  POST            connection setRequestProperty  Content-type    application json charset UTF-8            connection setReadTimeout 60000           connection setConnectTimeout 60000           connection connect      setting the outputstream          dataOutputStream   new DataOutputStream connection getOutputStream       i use this to see in the logcat what i am sending          Log d  OUTPUT STREAM     param           dataOutputStream writeBytes param           dataOutputStream flush            dataOutputStream close             InputStream in   new BufferedInputStream connection getInputStream             BufferedReader reader   new BufferedReader new InputStreamReader in            result   new StringBuilder            String line    here the string is constructed           while   line   reader readLine       null                        result append line               i use this log to see what its comming in the response            Log d  INPUTSTREAM    result toString       instancing a json   with the String that contains the server response          jResponse new JSONObject result toString                catch  IOException e            e printStackTrace            return jResponse null        catch  JSONException e                e printStackTrace            return jResponse null            connection disconnect        return jResponse

User · Answer

Although there are already excellent answers are provided by users such as encouraging use of GSON etc  I would like to suggest use of org json  It includes most of GSON functionalities  It also allows you to pass json string as an argument to it s JSONObject and it will take care of rest e g   JSONObject json   new JSONObject  some random json string     This functionality make it my personal favorite

User · Answer

I am surprised these have not been mentioned  but instead of using bare-bones rather manual process with json org s little package  GSon and Jackson are much more convenient to use  So    GSON Jackson   So you can actually bind to your own POJOs  not some half-assed tree nodes or Lists and Maps   and at least Jackson allows binding to such things too  perhaps GSON as well  not sure   JsonNode  Map  List  if you really want these instead of  real  objects   EDIT 19-MAR-2014   Another new contender is Jackson jr library  it uses same fast Streaming parser generator as Jackson  jackson-core   but data-binding part is tiny  50kB   Functionality is more limited  no annotations  just regular Java Beans   but performance-wise should be fast  and initialization  first-call  overhead very low as well  So it just might be good choice  especially for smaller apps

[android] Sending and Parsing JSON Objects in Android

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