Java how to use UrlConnection to post request with authorization

Question

I would like to generate POST request to a server which requires authentication  I tried to use the following method   private synchronized String CreateNewProductPOST  String urlString  String encodedString  String title  String content  Double price  String tags         String data    product title      URLEncoder encode title                      amp product content      URLEncoder encode content                       amp product price      URLEncoder encode price toString                        amp tags     tags      try           URL url   new URL urlString           URLConnection conn          conn   url openConnection            conn setRequestProperty   Authorization    Basic     encodedString           conn setDoOutput true           conn setDoInput true           OutputStreamWriter wr   new OutputStreamWriter conn getOutputStream             wr write data           wr flush                Get the response          BufferedReader rd   new BufferedReader new InputStreamReader conn getInputStream               String line           while   line   rd readLine       null                    Process line                            wr close             rd close             return rd toString          catch  MalformedURLException e             e printStackTrace            return e getMessage              catch  IOException e             e printStackTrace            return e getMessage               but the server doesn t receive the authorization data  The line which is supposed to add authorization data is the following   conn setRequestProperty   Authorization    Basic     encodedString     and the line   BufferedReader rd   new BufferedReader new InputStreamReader conn getInputStream         also throws an IOException   Anyway I would be very thankful if anyone could suggest any fix of the logic above in order to enable authorization using POST with UrlConnection   but obviously it doesn t work as it is supposed to although if the same logic is used for GET request everything works fine

User · Answer

I ran into this problem today and none of the solutions posted here worked. However, the code posted here worked for a POST request:

// HTTP POST request
private void sendPost() throws Exception {

    String url = "https://selfsolve.apple.com/wcResults.do";
    URL obj = new URL(url);
    HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

    //add reuqest header
    con.setRequestMethod("POST");
    con.setRequestProperty("User-Agent", USER_AGENT);
    con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

    String urlParameters = "sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";

    // Send post request
    con.setDoOutput(true);
    DataOutputStream wr = new DataOutputStream(con.getOutputStream());
    wr.writeBytes(urlParameters);
    wr.flush();
    wr.close();

    int responseCode = con.getResponseCode();
    System.out.println("\nSending 'POST' request to URL : " + url);
    System.out.println("Post parameters : " + urlParameters);
    System.out.println("Response Code : " + responseCode);

    BufferedReader in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }
    in.close();

    //print result
    System.out.println(response.toString());

}

It turns out that it's not the authorization that's the problem. In my case, it was an encoding problem. The content-type I needed was application/json but from the Java documentation:

static String encode(String s, String enc)
Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme.

The encode function translates the string into application/x-www-form-urlencoded.

Now if you don't set a Content-Type, you may get a 415 Unsupported Media Type error. If you set it to application/json or anything that's not application/x-www-form-urlencoded, you get an IOException. To solve this, simply avoid the encode method.

For this particular scenario, the following should work:

String data = "product[title]=" + title +
                "&product[content]=" + content + 
                "&product[price]=" + price.toString() +
                "&tags=" + tags;

Another small piece of information that might be helpful as to why the code breaks when creating the buffered reader is because the POST request actually only gets executed when conn.getInputStream() is called.

User · Answer

A fine example found here  Powerlord got it right  below  for POST you need HttpURLConnection  instead   Below is the code to do that       URL url   new URL urlString       URLConnection conn   url openConnection        conn setDoOutput true       conn setRequestProperty   Authorization   encodedCredentials        OutputStreamWriter writer   new OutputStreamWriter conn getOutputStream          writer write data       writer flush        String line      BufferedReader reader   new BufferedReader new                                       InputStreamReader conn getInputStream          while   line   reader readLine       null          System out println line             writer close        reader close      Change URLConnection to HttpURLConnection  to make it POST request       HttpURLConnection conn    HttpURLConnection  url openConnection        conn setRequestMethod  POST      Suggestion     in comments    You might need to set these properties too   conn setRequestProperty   Content-type    application x-www-form-urlencoded    conn setRequestProperty   Accept

User · Answer

On API 22 The Use Of BasicNamevalue Pair is depricated  instead use the HASMAP for that  To know more about the HasMap visit here more on hasmap developer android    package com yubraj sample datamanager   import android content Context  import android os AsyncTask  import android os Bundle  import android text TextUtils  import android util Log   import com yubaraj sample utilities GeneralUtilities    import java io BufferedInputStream  import java io BufferedReader  import java io BufferedWriter  import java io IOException  import java io InputStream  import java io InputStreamReader  import java io OutputStream  import java io OutputStreamWriter  import java io UnsupportedEncodingException  import java net HttpURLConnection  import java net URL  import java net URLEncoder  import java util HashMap  import java util Map   import javax net ssl HttpsURLConnection          Created by yubraj on 7 30 15      public class ServerRequestHandler       private static final String TAG    Server Request       OnServerRequestComplete listener       public ServerRequestHandler                public void doServerRequest HashMap lt String  String gt  parameters  String url  int requestType  OnServerRequestComplete listener            debug  ServerRequest    server request called  url        url           if listener    null               this listener   listener                    try               new BackgroundDataSync getPostDataString parameters   url  requestType  execute                debug TAG     asnyc task called              catch  Exception e                e printStackTrace                         public void doServerRequest HashMap lt String  String gt  parameters  String url  int requestType           doServerRequest parameters  url  requestType  null              public interface OnServerRequestComplete          void onSucess Bundle bundle           void onFailed int status code  String mesage  String url              public void setOnServerRequestCompleteListener OnServerRequestComplete listener           this listener   listener             private String getPostDataString HashMap lt String  String gt  params  throws UnsupportedEncodingException           StringBuilder result   new StringBuilder            boolean first   true          for Map Entry lt String  String gt  entry   params entrySet                 if  first                  first   false              else                 result append   amp                  result append URLEncoder encode entry getKey     UTF-8                 result append                   result append URLEncoder encode entry getValue     UTF-8                        return result toString               class BackgroundDataSync extends AsyncTask lt String  Void   String gt           String params          String mUrl          int request type           public BackgroundDataSync String params  String url  int request type               this mUrl   url              this params   params              this request type   request type                      Override         protected void onPreExecute                 super onPreExecute                        Override         protected String doInBackground String    urls                debug TAG   in Background  urls       urls length               HttpURLConnection connection                  debug TAG   in Background  url       mUrl                   String response                       switch  request type                        case 1                          try                               connection   iniitializeHTTPConnection mUrl   POST                                OutputStream os   connection getOutputStream                                BufferedWriter writer   new BufferedWriter                                      new OutputStreamWriter os   UTF-8                                 writer write params                               writer flush                                writer close                                os close                                int responseCode   connection getResponseCode                                if  responseCode    HttpsURLConnection HTTP OK                                  String line                              BufferedReader br new BufferedReader new InputStreamReader connection getInputStream                                  while   line br readLine       null                                    response  line                                                                  response   getDataFromInputStream new InputStreamReader connection getInputStream                                    else                                   response                                                               catch  IOException e                                e printStackTrace                                                      break                      case 0                          connection   iniitializeHTTPConnection mUrl   GET                             try                               if  connection getResponseCode      connection HTTP OK                                    response   getDataFromInputStream new InputStreamReader connection getInputStream                                                              catch  Exception e                                e printStackTrace                                response                                                         break                                    return response                        Override         protected void onPostExecute String s                super onPostExecute s               if TextUtils isEmpty s     s length      0                   listener onFailed DbConstants NOT FOUND   Data not found   mUrl                             else                  Bundle bundle   new Bundle                    bundle putInt DbConstants STATUS CODE  DbConstants HTTP OK                   bundle putString DbConstants RESPONSE  s                   bundle putString DbConstants URL  mUrl                   listener onSucess bundle                               System out println  Data Obtained       s                      private HttpURLConnection iniitializeHTTPConnection String url  String requestType                try                   debug  ServerRequest    url       url    requestType       requestType                   URL link   new URL url                   HttpURLConnection conn    HttpURLConnection  link openConnection                    conn setRequestMethod requestType                   conn setDoInput true                   conn setDoOutput true                   return conn                            catch Exception e                   e printStackTrace                              return null                       private String getDataFromInputStream InputStreamReader reader           String line          String response               try                BufferedReader br   new BufferedReader reader               while   line   br readLine       null                    response    line                   debug  ServerRequest    response length       response length                                     catch  Exception e               e printStackTrace                      return response             private void debug String tag  String string            Log d tag  string             and Just call the function when you needed to get the data from server either by post or get like this  HashMap lt String  String gt params   new HashMap lt String  String gt                         params put  action    request sample                        params put  name   uname                       params put  message   umsg                       params put  email   getEmailofUser                         params put  type    bio    dq doServerRequest params   your url   DbConstants METHOD POST                       dq setOnServerRequestCompleteListener new ServerRequestHandler OnServerRequestComplete                              Override                         public void onSucess Bundle bundle                                debug  data   bundle getString DbConstants RESPONSE                                                                                    Override                         public void onFailed int status code  String mesage  String url                                debug  sample   mesage                                                        Now it is complete Enjoy    Comment it if find any problem

User · Answer

To do oAuth authentication to  external app  INSTAGRAM  Step 3  get the token after receiving the code  Only code below worked for me  Worth to state also that it worked for me using some localhost URL with a callback servlet configured with name  callback in web xml and callback URL registered  e g  localhost 8084 MyAPP docs insta callback  BUT after successfully completed authentication steps  using same external site  INSTAGRAM  to do GET of Tags or MEDIA to retrieve JSON data using initial method didn t work   Inside my servlet to do GET using url like  e g  api instagram com v1 tags MYTAG media recent access token MY TOKEN only method found HERE worked   Thanks to all contributors          URL url   new URL httpurl           HashMap lt String  String gt  params   new HashMap lt String  String gt             params put  client id   id           params put  client secret   secret           params put  grant type    authorization code            params put  redirect uri   redirect           params put  code   code       your INSTAGRAM code received          Set set   params entrySet            Iterator i   set iterator            StringBuilder postData   new StringBuilder            for  Map Entry lt String  String gt  param   params entrySet                  if  postData length      0                    postData append   amp                               postData append URLEncoder encode param getKey     UTF-8                 postData append                   postData append URLEncoder encode String valueOf param getValue      UTF-8                       byte   postDataBytes   postData toString   getBytes  UTF-8             HttpsURLConnection conn    HttpsURLConnection  url openConnection            conn setRequestMethod  POST            conn setRequestProperty  Content-Type    application x-www-form-urlencoded            conn setRequestProperty  Content-Length   String valueOf postDataBytes length            conn setDoOutput true           conn getOutputStream   write postDataBytes           BufferedReader reader   new BufferedReader new InputStreamReader conn getInputStream     UTF-8             StringBuilder builder   new StringBuilder            for  String line   null   line   reader readLine       null                 builder append line  append   n                      reader close            conn disconnect            System out println  INSTAGRAM token returned    builder toString

User · Answer

I don t see anywhere in the code where you specify that this is a POST request   Then again  you need a java net HttpURLConnection to do that     In fact  I highly recommend using HttpURLConnection instead of URLConnection  with conn setRequestMethod  POST    and see if it still gives you problems

User · Answer

i was looking information about how to do a POST request  I need to specify that mi request is a POST request because  i m working with RESTful web services that only uses POST methods  and if the request isn t post  when i try to do the request i receive an HTTP error 405  I assure that my code isn t wrong doing the next  I create a method in my web service that is called through GET request and i point my application to consume that web service method and it works   My code is the next       URL server   null      URLConnection conexion   null      BufferedReader reader   null      server   new URL  http   localhost 8089 myApp resources webService        conexion   server openConnection        reader   new BufferedReader new InputStreamReader server openStream          System out println reader readLine

User · Answer

To send a POST request call           connection setDoOutput true      Triggers POST    If you want to sent text in the request use           java io OutputStreamWriter wr   new java io OutputStreamWriter connection getOutputStream             wr write textToSend           wr flush

User · Answer

HTTP authorization does not differ between GET and POST requests  so I would first assume that something else is wrong  Instead of setting the Authorization header directly  I would suggest using the java net Authorization class  but I am not sure if it solves your problem  Perhaps your server is somehow configured to require a different authorization scheme than  basic  for post requests

[java] Java: how to use UrlConnection to post request with authorization?

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