How to send POST request in JSON using HTTPClient in Android

Question

I m trying to figure out how to POST JSON from Android by using HTTPClient  I ve been trying to figure this out for a while  I have found plenty of examples online  but I cannot get any of them to work   I believe this is because of my lack of JSON networking knowledge in general   I know there are plenty of examples out there but could someone point me to an actual tutorial  I m looking for a step by step process with code and explanation of why you do each step  or of what that step does  It doesn t need to be a complicated  simple will suffice   Again  I know there are a ton of examples out there  I m just really looking for an example with an explanation of what exactly is happening and why it is doing that way    If someone knows about a good Android book on this  then please let me know   Thanks again for the help  terrance  here is the code I described below  public void shNameVerParams   throws Exception       String path     removed      HashMap  params   new HashMap          params put new String  Name     Value          params put new String  Name     Value          try           HttpClient SendHttpPost path  params         catch  Exception e               TODO Auto-generated catch block         e printStackTrace

User · Answer

Too much code for this task  checkout this library https   github com kodart Httpzoid Is uses GSON internally and provides API that works with objects  All JSON details are hidden   Http http   HttpFactory create context   http get  http   example com users        handler new ResponseHandler lt User   gt               Override         public void success User   users  HttpResponse response                     execute

User · Answer

I recommend using this HttpURLConnectioninstead HttpGet  As HttpGet is already deprecated in Android API level 22   HttpURLConnection httpcon    String url   null  String data   null  String result   null  try       Connect   httpcon    HttpURLConnection    new URL  url  openConnection        httpcon setDoOutput true     httpcon setRequestProperty  Content-Type    application json      httpcon setRequestProperty  Accept    application json      httpcon setRequestMethod  POST      httpcon connect         Write          OutputStream os   httpcon getOutputStream      BufferedWriter writer   new BufferedWriter new OutputStreamWriter os   UTF-8       writer write data     writer close      os close         Read           BufferedReader br   new BufferedReader new InputStreamReader httpcon getInputStream    UTF-8        String line   null     StringBuilder sb   new StringBuilder                while   line   br readLine       null          sb append line                    br close        result   sb toString       catch  UnsupportedEncodingException e        e printStackTrace      catch  IOException e        e printStackTrace

User · Answer

There are couple of ways to establish HHTP connection and fetch data from a RESTFULL web service  The most recent one is GSON  But before you proceed to GSON you must have some idea of the most traditional way of creating an HTTP Client and perform data communication with a remote server  I have mentioned both the methods to send POST  amp  GET requests using HTTPClient          This method is used to process GET requests to the server          param url      return String     throws IOException     public static String connect String url  throws IOException        HttpGet httpget   new HttpGet url       HttpResponse response      HttpParams httpParameters   new BasicHttpParams           Set the timeout in milliseconds until a connection is established         The default value is zero  that means the timeout is not used       int timeoutConnection   60 1000      HttpConnectionParams setConnectionTimeout httpParameters  timeoutConnection          Set the default socket timeout  SO TIMEOUT          in milliseconds which is the timeout for waiting for data      int timeoutSocket   60 1000       HttpConnectionParams setSoTimeout httpParameters  timeoutSocket       HttpClient httpclient   new DefaultHttpClient httpParameters       try            response   httpclient execute httpget            HttpEntity entity   response getEntity            if  entity    null                InputStream instream   entity getContent                result   convertStreamToString instream                 instream close                         catch  ClientProtocolException e            Utilities showDLog  connect   ClientProtocolException -  e         catch  IOException e            Utilities showDLog  connect   IOException -  e              return result              This method is used to send POST requests to the server          param URL     param paramenter     return result of server response     static public String postHTPPRequest String URL  String paramenter                HttpParams httpParameters   new BasicHttpParams           Set the timeout in milliseconds until a connection is established         The default value is zero  that means the timeout is not used       int timeoutConnection   60 1000      HttpConnectionParams setConnectionTimeout httpParameters  timeoutConnection          Set the default socket timeout  SO TIMEOUT          in milliseconds which is the timeout for waiting for data      int timeoutSocket   60 1000       HttpConnectionParams setSoTimeout httpParameters  timeoutSocket       HttpClient httpclient   new DefaultHttpClient httpParameters       HttpPost httppost   new HttpPost URL       httppost setHeader  Content-Type    application json        try           if  paramenter    null                StringEntity tmp   null              tmp   new StringEntity paramenter   UTF-8                httppost setEntity tmp                     HttpResponse httpResponse   null          httpResponse   httpclient execute httppost           HttpEntity entity   httpResponse getEntity            if  entity    null                InputStream input   null              input   entity getContent                String res   convertStreamToString input               return res                        catch  Exception e            System out print e toString               return null

User · Answer

In this answer I am using an example posted by Justin Grammens   About JSON  JSON stands for JavaScript Object Notation  In JavaScript properties can be referenced both like this object1 name and like this  object  name     The example from the article uses this bit of JSON   The Parts A fan object with email as a key and foo bar com as a value      fan              email    foo bar com            So the object equivalent would be fan email  or fan  email     Both would have the same value  of  foo bar com    About HttpClient Request  The following is what our author used to make a HttpClient Request  I do not claim to be an expert at all this so if anyone has a better way to word some of the terminology feel free   public static HttpResponse makeRequest String path  Map params  throws Exception          instantiates httpclient to make request     DefaultHttpClient httpclient   new DefaultHttpClient           url with the post data     HttpPost httpost   new HttpPost path          convert parameters into JSON object     JSONObject holder   getJsonObjectFromMap params          passes the results to a string builder entity     StringEntity se   new StringEntity holder toString            sets the post request as the resulting string     httpost setEntity se         sets a request header so the page receving the request       will know what to do with it     httpost setHeader  Accept    application json        httpost setHeader  Content-type    application json           Handles what is returned from the page      ResponseHandler responseHandler   new BasicResponseHandler        return httpclient execute httpost  responseHandler       Map  If you are not familiar with the Map data structure please take a look at the Java Map reference  In short  a map is similar to a dictionary or a hash   private static JSONObject getJsonObjectFromMap Map params  throws JSONException          all the passed parameters from the post request       iterator used to loop through all the parameters       passed in the post request     Iterator iter   params entrySet   iterator           Stores JSON     JSONObject holder   new JSONObject           using the earlier example your first entry would get email       and the inner while would get the value which would be  foo bar com           fan    email    foo bar com             While there is another entry     while  iter hasNext                     gets an entry in the params         Map Entry pairs    Map Entry iter next               creates a key for Map         String key    String pairs getKey               Create a new map         Map m    Map pairs getValue                  object for storing Json         JSONObject data   new JSONObject               gets the value         Iterator iter2   m entrySet   iterator            while  iter2 hasNext                           Map Entry pairs2    Map Entry iter2 next                data put  String pairs2 getKey     String pairs2 getValue                          puts email and  foo bar com   together in map         holder put key  data             return holder         Please feel free to comment on any questions that arise about this post or if I have not made something clear or if I have not touched on something that your still confused about    etc whatever pops in your head really      I will take down if Justin Grammens does not approve  But if not then thanks Justin for being cool about it    Update   I just happend to get a comment about how to use the code and realized that there was a mistake in the return type   The method signature was set to return a string but in this case it wasnt returning anything  I changed the signature  to HttpResponse and will refer you to this link on Getting Response Body of HttpResponse the path variable is the url and I updated to fix a mistake in the code

User · Answer

Here is an alternative solution to  Terrance s answer  You can easly outsource the conversion  The Gson library does wonderful work converting various data structures into JSON and the other way around   public static void execute         Map lt String  String gt  comment   new HashMap lt String  String gt         comment put  subject    Using the GSON library        comment put  message    Using libraries is convenient         String json   new GsonBuilder   create   toJson comment  Map class       makeRequest  http   192 168 0 1 3000 post 77 comments   json      public static HttpResponse makeRequest String uri  String json        try           HttpPost httpPost   new HttpPost uri           httpPost setEntity new StringEntity json            httpPost setHeader  Accept    application json            httpPost setHeader  Content-type    application json            return new DefaultHttpClient   execute httpPost         catch  UnsupportedEncodingException e            e printStackTrace          catch  ClientProtocolException e            e printStackTrace          catch  IOException e            e printStackTrace              return null      Similar can be done by using Jackson instead of Gson  I also recommend taking a look at Retrofit which hides a lot of this boilerplate code for you  For more experienced developers I recommend trying out RxAndroid

[android] How to send POST request in JSON using HTTPClient in Android?

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