Java Post request with form data

Question

I want to make a simple POST call in Java,
I am getting a 200 response code but, with the wrong response message,
I am told there is a different way to make a Post call when using a form data .

Following is my current Java code to make the post call -

private String makePostCall(){
        try {
            String url = "http://someIp/trusted";
            HttpClient client = new DefaultHttpClient();
            HttpPost post = new HttpPost(url);

            // add header
            List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
            urlParameters.add(new BasicNameValuePair("username", "app_user"));

            post.setEntity(new UrlEncodedFormEntity(urlParameters));

            HttpResponse response = client.execute(post);
            System.out.println("\nSending 'POST' request to URL : " + url);
            System.out.println("Post parameters : " + post.getEntity());
            System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

            BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer result = new StringBuffer();
            String line = "";
            while ((line = rd.readLine()) != null) {
                result.append(line);
            }

            System.out.println(result.toString());
            return result.toString();

        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

Following is the Post call sample that is working through Postman app -

I am referring the following website -
https://www.mkyong.com/java/how-to-send-http-request-getpost-in-java/

The expected outcome of the post call is supposed to be a Token ie. a String value, current response is -1.

Answer 1

These answers are correct, but I struggled to get this to a working code. So, let me provide a general and working answer which can be reused.

private static RequestConfig requestConfig = RequestConfig.custom().build();

public HttpResponse postWithFormData(String url, List<NameValuePair> params) throws IOException {
        // building http client
        HttpClient httpClient = HttpClientBuilder.create().setDefaultRequestConfig(requestConfig).build();
        HttpPost request = new HttpPost(url);

        // adding the form data
        request.setEntity(new UrlEncodedFormEntity(params));
        return httpClient.execute(request);
    }

List<NameValuePair> urlParameters = new ArrayList<>();

// add any number of form data
urlParameters.add(new BasicNameValuePair("form_key_1", "form_value_1");
urlParameters.add(new BasicNameValuePair("form_key_2", "form_value_2");

// Getting the HTTP Response and processing it
HttpResponse response = postWithFormData("http_url", urlParameters);
HttpEntity entity = response.getEntity();
// String of the response
String responseString = EntityUtils.toString(entity);
// JSON of the response (use this only if the response is a JSON)
JSONObject responseObject = new JSONObject(responseString);

These are my main imports, in case anyone gets confused on what to import.

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.json.JSONObject;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;

Answer 2

Give a try by setting content type multipart/form-data explicitly,

post.setHeader("Content-Type", "multipart/form-data");

In your code ,

post.setEntity(new UrlEncodedFormEntity(urlParameters)); 
post.setHeader("Content-Type", "multipart/form-data");