Apache HttpClient JSON Post - json

Question

I try to send directly a JSON string with HttpClient 4.4 in an application (SWT/JFace) :
public String postJSON(String urlToRead,Object o) throws ClientProtocolException, IOException {
String result="";
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
HttpPost postRequest = new HttpPost(urlToRead);
postRequest.setHeader("content-type", "application/x-www-form-urlencoded");
//postRequest.setHeader("Content-type", "application/json");
//{"mail":"admin#localhost", "password":"xyz"}
String jsonString=gson.toJson(o);
StringEntity params =new StringEntity(jsonString);
params.setContentType("application/json");
params.setContentEncoding("UTF-8");
postRequest.setEntity(params);
ResponseHandler<String> responseHandler = new BasicResponseHandler();
result = httpClient.execute(postRequest, responseHandler);
}finally {
httpClient.close();;
}
return result;
}
I try to get the response from the server (Apache/PHP) with $POST
the correct content of $POST should be :
array("mail"=>"admin#localhost","password"=>"xyz")
When I use content-type : application/x-www-form-urlencoded
$POST content is :
array( "{"mail":"admin#localhost","password":"xyz"}"=> )
When I use content-type : application/json
$POST is empty : array()
Is there a way to post the JSON string with HttpClient or should I use an ArrayList<NameValuePair> and add each member of my object in the entity ?

Answer 1

I put the "NameValuePair" solution (not in the comments, the answer is too long), but I thought StringEntity was able to understand the JSON see How to POST JSON request using Apache HttpClient? and there: HTTP POST using JSON in Java
public String postJSON(String urlToRead,Object o) throws ClientProtocolException, IOException {
String result="";
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
HttpPost postRequest = new HttpPost(urlToRead);
postRequest.setHeader("content-type", "application/x-www-form-urlencoded");
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
//{"mail":"admin#localhost", "password":"xyz"}
JsonElement elm= gson.toJsonTree(o);
JsonObject jsonObj=elm.getAsJsonObject();
for(Map.Entry<String, JsonElement> entry:jsonObj.entrySet()){
nameValuePairs.add(new BasicNameValuePair(entry.getKey(),entry.getValue().getAsString()));
}
postRequest.setEntity(new UrlEncodedFormEntity(nameValuePairs));
ResponseHandler<String> responseHandler = new BasicResponseHandler();
result = httpClient.execute(postRequest, responseHandler);
}finally {
httpClient.close();;
}
return result;
}
This way, the content of $POST is correct : array("mail"=>"admin#localhost","password"=>"xyz")