HTTP POST using JSON in Java

Question

I would like to make a simple HTTP POST using JSON in Java   Let s say the URL is www site com  and it takes in the value   name   myname   age   20   labeled as  details  for example    How would I go about creating the syntax for the POST   I also can t seem to find a POST method in the JSON Javadocs

User · Answer

I found this question looking for solution about how to send post request from java client to Google Endpoints. Above answers, very likely correct, but not work in case of Google Endpoints.

Solution for Google Endpoints.

Request body must contains only JSON string, not name=value pair.

Content type header must be set to "application/json".

post("http://localhost:8888/_ah/api/langapi/v1/createLanguage",
                   "{\"language\":\"russian\", \"description\":\"dsfsdfsdfsdfsd\"}");



public static void post(String url, String json ) throws Exception{
  String charset = "UTF-8"; 
  URLConnection connection = new URL(url).openConnection();
  connection.setDoOutput(true); // Triggers POST.
  connection.setRequestProperty("Accept-Charset", charset);
  connection.setRequestProperty("Content-Type", "application/json;charset=" + charset);

  try (OutputStream output = connection.getOutputStream()) {
    output.write(json.getBytes(charset));
  }

  InputStream response = connection.getInputStream();
}

It sure can be done using HttpClient as well.

User · Answer

Try this code   HttpClient httpClient   new DefaultHttpClient     try       HttpPost request   new HttpPost  http   yoururl        StringEntity params  new StringEntity  details    name     myname     age     20            request addHeader  content-type    application json        request addHeader  Accept   application json        request setEntity params       HttpResponse response   httpClient execute request           handle response here     catch  Exception ex           handle exception here   finally       httpClient getConnectionManager   shutdown

User · Answer

For Java 11 you can use new HTTP client    HttpClient client   HttpClient newHttpClient        HttpRequest request   HttpRequest newBuilder            uri URI create  http   localhost api             header  Content-Type    application json            POST ofInputStream    - gt  getClass   getResourceAsStream                some-data json              build         client sendAsync request  BodyHandlers ofString             thenApply HttpResponse  body           thenAccept System out  println           join      You can use publisher from InputStream  String  File  Converting JSON to the String or IS you can with Jackson

User · Answer

You can use the following code with Apache HTTP   String payload       name      myname      age      20      post setEntity new StringEntity payload  ContentType APPLICATION JSON     response   client execute request     Additionally you can create a json object and put in fields into the object like this  HttpPost post   new HttpPost URL   JSONObject payload   new JSONObject    payload put  name    myName    payload put  age    20    post setEntity new StringEntity payload toString    ContentType APPLICATION JSON

User · Answer

It s probably easiest to use HttpURLConnection   http   www xyzws com Javafaq how-to-use-httpurlconnection-post-data-to-web-server 139  You ll use JSONObject or whatever to construct your JSON  but not to handle the network  you need to serialize it and then pass it to an HttpURLConnection to POST

User · Answer

momo s answer for Apache HttpClient  version 4 3 1 or later  I m using JSON-Java to build my JSON object   JSONObject json   new JSONObject    json put  someKey    someValue         CloseableHttpClient httpClient   HttpClientBuilder create   build     try       HttpPost request   new HttpPost  http   yoururl        StringEntity params   new StringEntity json toString         request addHeader  content-type    application json        request setEntity params       httpClient execute request      handle response here      catch  Exception ex           handle exception here   finally       httpClient close

User · Answer

I recomend http-request built on apache http api   HttpRequest lt String gt  httpRequest   HttpRequestBuilder createPost yourUri  String class       responseDeserializer ResponseDeserializer ignorableDeserializer    build     public void send       ResponseHandler lt String gt  responseHandler   httpRequest execute  details   yourJsonData       int statusCode   responseHandler getStatusCode       String responseContent   responseHandler orElse null      returns Content from response  If content isn t present returns null       If you want send JSON as request body you can     ResponseHandler lt String gt  responseHandler   httpRequest executeWithBody yourJsonData     I higly recomend read documentation before use

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protected void sendJson final String play  final String prop         Thread t   new Thread          public void run             Looper prepare      For Preparing Message Pool for the childThread         HttpClient client   new DefaultHttpClient            HttpConnectionParams setConnectionTimeout client getParams    1000     Timeout Limit         HttpResponse response          JSONObject json   new JSONObject                 try                   HttpPost post   new HttpPost  http   192 168 0 44 80                    json put  play   play                   json put  Properties   prop                   StringEntity se   new StringEntity json toString                     se setContentType new BasicHeader HTTP CONTENT TYPE   application json                     post setEntity se                   response   client execute post                      Checking response                    if  response    null                        InputStream in   response getEntity   getContent      Get the data in the entity                                  catch  Exception e                    e printStackTrace                    showMessage  Error    Cannot Estabilish Connection                               Looper loop      Loop in the message queue                      t start

User · Answer

You can make use of Gson library to convert your java classes to JSON objects   Create a pojo class for variables you want to send as per above Example     name   myname   age   20     becomes  class pojo1      String name     String age       generate setter and getters     once you set the variables in pojo1 class you can send that using the following code  String       postUrl          www site com     put in your url Gson         gson            new Gson    HttpClient   httpClient      HttpClientBuilder create   build    HttpPost     post            new HttpPost postUrl   StringEntity postingString   new StringEntity gson toJson pojo1     gson tojson   converts your pojo to json post setEntity postingString   post setHeader  Content-type    application json    HttpResponse  response   httpClient execute post     and these are the imports  import org apache http HttpEntity  import org apache http HttpResponse  import org apache http client HttpClient  import org apache http client methods HttpPost  import org apache http entity StringEntity  import org apache http impl client HttpClientBuilder    and for GSON  import com google gson Gson

User · Answer

Here is what you need to do   Get the Apache HttpClient  this would enable you to make the required request Create an HttpPost request with it and add the header application x-www-form-urlencoded Create a StringEntity that you will pass JSON to it Execute the call  The code roughly looks like  you will still need to debug it and make it work       Deprecated HttpClient httpClient   new DefaultHttpClient    HttpClient httpClient   HttpClientBuilder create   build    try       HttpPost request   new HttpPost  quot http   yoururl quot        StringEntity params   new StringEntity  quot details    quot name  quot    quot xyz  quot    quot age  quot    quot 20  quot    quot        request addHeader  quot content-type quot    quot application x-www-form-urlencoded quot        request setEntity params       HttpResponse response   httpClient execute request     catch  Exception ex      finally           Deprecated httpClient getConnectionManager   shutdown

User · Answer

Java 8 with apache httpClient 4  CloseableHttpClient client   HttpClientBuilder create   build    HttpPost httpPost   new HttpPost  www site com      String json    details    name     myname     age     20                try               StringEntity entity   new StringEntity json               httpPost setEntity entity                   set your POST request headers to accept json contents             httpPost setHeader  Accept    application json                httpPost setHeader  Content-type    application json                 try                      your closeablehttp response                 CloseableHttpResponse response   client execute httpPost                       print your status code from the response                 System out println response getStatusLine   getStatusCode                         take the response body as a json formatted string                  String responseJSON   EntityUtils toString response getEntity                         convert parse the json formatted string to a json object                 JSONObject jobj   new JSONObject responseJSON                      print your response body that formatted into json                 System out println jobj                  catch  IOException e                    e printStackTrace                  catch  JSONException e                     e printStackTrace                             catch  UnsupportedEncodingException e                e printStackTrace

[java] HTTP POST using JSON in Java

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