We Keep Coding

I am confused about something in python to send an HTTP request that I am trying to recreate in java

My friend recently sent me this code:
requests.post("example.com", headers = {'authorization': token}, json = {'content' : message})
it is in python. It is meant to send an HTTP post request to example.com and I am trying to convert it to java.
So far, I have this:
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
//url is defined farther up in the code.
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("Authorization", token);
However, in my friends code he had 2 different parts that were headers={} and json={}
I don't know how I would do this in java. I am confused what the difference between headers and json is. How would I choose the content of the message? please let me know.

So from what I understand you having issues adding the json content to the request?
setRequestProperty() in java is the same in python as doing the following:
headers = {}
headers['Content-Type'] = "application/json"
headers['Authorization'] = token
I haven't written in Java for a long time but from what I have read you need to do the following:
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json; utf-8");
connection.setRequestProperty("Authorization", token);
connection.setDoOutput(true);
// This part sends the json data to the output stream with the headers defined above sent with the data
String inputString = "{variable1: "myvariable1", variable2; "myvariable2"}";
try(OutputStream stream = con.getOutputStream()){
byte[] input = inputString.getBytes("utf-8");
stream.write(input, 0, input.length);
}
You are already setting the headers via "setRequestProperty()" you just need to send the data as well.

Java doesn't send HTTP POST Request

I'm implementing some simple java class in order to send an HTTP Request with POST method and also another java class in order to receive it.
The server works fine when I make a POST request by means of my browser(Chrome), or an application(I have used Postman in this case) but it ends up with problem when I send HTTP Request with java!
My sending HTTP class is "Sender.java", containing the following snippet:
String url = "http://localhost:8082/";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
// Setting basic post request
con.setRequestMethod("POST");
//con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
//con.setRequestProperty("Content-Type","text/plain");
// Send post request
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
os.write("Just Some Text".getBytes("UTF-8"));
os.flush();
os.close();
//connect to the Server(resides at Server.java)
con.connect();
I have commented some lines of code setting Headers like "Accept-Language" and "Content-Type" because I don't know whether or not are these headers required for the java program to work out?
The server is another java program named "Server.java". Here is the snippet related to reading HTTP Request made by the Sender.java(if need be).
int servPort = 8082;
// Create a server socket to accept HTTP client connection requests
HttpServer server = HttpServer.create(new InetSocketAddress(servPort), 0);
System.out.println("server started at " + servPort);
server.createContext("/", new PostHandler());//PostHandler implements HttpHandler
server.setExecutor(null);
server.start();
All I want is to send a plaintext as the body of my HTTP Request with the Post method. I have read plenty of sites and even related questions at this site. But it still doesn't work out. In other words, whenever I create an HTTP Request from "Sender.java", nothing appears at "Server.java". I just want to know what's wrong with my snippets and how should I fix that?

I tested this and it's working:
//Sender.java
String url = "http://localhost:8082/";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
con.setRequestMethod("POST");
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
os.write("Just Some Text".getBytes("UTF-8"));
os.flush();
int httpResult = con.getResponseCode();
con.disconnect();
As you can see, connect is not necessary. The key line is
int httpResult = con.getResponseCode();

When you send a POST form using the browser, it sends the form in a certain format, defined in RFC1866, you have to recreate this on Java when making a post request.
With this format, its important you set the Content-Type header to application/x-www-form-urlencoded, and pass the body as you would do in a url with a get request.
Borrowing some code of my previous answer to POST in Java:
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
// Setting basic post request
con.setRequestMethod("POST");
Map<String,String> form = new HashMap<>();
// Define the fields
form.put("username", "root");
form.put("password", "sjh76HSn!"); // This is a fake password obviously
// Build the body
StringJoiner sj = new StringJoiner("&");
for(Map.Entry<String,String> entry : arguments.entrySet())
sj.add(URLEncoder.encode(entry.getKey(), "UTF-8") + "="
+ URLEncoder.encode(entry.getValue(), "UTF-8"));
byte[] out = sj.toString().getBytes(StandardCharsets.UTF_8);
int length = out.length;
// Prepare our `con` object
con.setFixedLengthStreamingMode(length);
con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
con.connect();
try (OutputStream os = con.getOutputStream()) {
os.write(out);
}

Maybe “localhost” in the sender url does not resolve to the same ip that the server binds to? Try changing to 127.0.0.1 or your actual IP address.

try with PrintStream
String url = "http://localhost:8082/";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
// Setting basic post request
con.setRequestMethod("POST");
//con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
//con.setRequestProperty("Content-Type","text/plain");
// Send post request
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
java.io.PrintStream printStream = new java.io.PrintStream(os);
printStream.println("Just Some Text");
con.getInputStream();//Send request
os.flush();
os.close();

Java - HttpURLConnection PUT request with empty body

I'm trying make a request with Java, when I call it using cURL like this, it works:
curl -X PUT http://serverurl.com/method/6eb276a2-5c79-4f6e-a4b5-a26b0e6848c7/action -H 'Content-Type: application/json' -H 'Token: cba5f12c-af55-480f-970e-525e446ef153' -H 'Content-Length : 0'
If I call the same request without passing header Content-Length param, I get 411 HTTP error, length required.
This is my code in Java:
URL url = new URL("http://serverurl.com/method/6eb276a2-5c79-4f6e-a4b5-a26b0e6848c7/action");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("PUT");
con.addRequestProperty("Content-Type", "application/json");
con.addRequestProperty("Token", "cba5f12c-af55-480f-970e-525e446ef153");
con.connect();
This request is getting a 411 HTTP code response. So, I tryed to add:
con.addRequestProperty("Content-Length", "0");
But it doesn't work, so I changed to:
URL url = new URL("http://serverurl.com/method/6eb276a2-5c79-4f6e-a4b5-a26b0e6848c7/action");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("PUT");
con.addRequestProperty("Content-Type", "application/json");
con.addRequestProperty("Token", "cba5f12c-af55-480f-970e-525e446ef153");
con.setDoOutput(true);
con.getOutputStream().close();
con.setFixedLengthStreamingMode(0);
con.connect();
But now I'm getting 400 HTTP code.
How can I do a PUT request with an empty body and setting content length to match the cURL call?

using the HttpUrlConnection, you should use the setRequestProperty method to add headers to your request. I can see your using the "addRequestProperty" which is probably why its not working. But refer to this link for more info https://juffalow.com/java/how-to-send-http-get-post-request-in-java and heres some code that i use to for a put request
URL url = new URL(BASE_URL+"/"+userID+".json");
urlRequest = (HttpURLConnection) url.openConnection();
urlRequest.setDoOutput(true);
urlRequest.setRequestMethod("PUT");
urlRequest.setRequestProperty("Content-Type", "application/json;
charset=UTF-8");
OutputStream os = urlRequest.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
osw.write("{\"idToken\":\""+"token"+"\"}");
osw.flush();
osw.close();
urlRequest.connect();
JsonParser jp = new JsonParser(); //from gson
JsonElement root = jp.parse(new InputStreamReader((InputStream)
urlRequest.getContent()));//Convert the input stream to a json element
JsonObject rootobj = root.getAsJsonObject();//Maybe an array or object
well thats just sample what i use... and i hope this works for you. Happy coding.

POST request working fine with POSTMAN/Advance rest client while giving 400 error with HttpUrlConnection

I am a newbie to HttpClient so not sure what's wrong I am doing. I am hitting one POST request through HttpUrlConnection. After sending the request when I check the logs it doesn't hit the entire request. My URL is https://www.example.com/product/pd/v1/gql when I check on the server, for URI, it shows v1/gql and give 400 error. while the same request works perfectly from Postman and advance rest client.
URL obj = new URL("https://www.example.com/product/pd/v1/gql/");
HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("User-Agent", USER_AGENT);
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Cookie", "_bb_vid=djfhhf");
JSONObject val = new JSONObject(gqlValue2);
JSONObject jObj = new JSONObject();
jObj.put(gqlKey1, gqlValue1);
jObj.put(gqlKey2, val);
System.out.println(jObj);
OutputStreamWriter wr = new
OutputStreamWriter(conn.getOutputStream());
wr.write(jObj.toString());
wr.flush();

POST from android to WCF Service (OData)

Edit:
After doing some more experimentation, I discovered that the request will only work if all of the values are quoted in the JSON string. That is to say that this won't work
{"Text":"test","RatingValue":0.0,"LocationID":5}
and this will
{"Text":"test","RatingValue":"0.0","LocationID":"5"}
What I don't understand is why. The first string seems to be a valid JSON string. Is this a quirk with WCF?
Original Post
I am trying to post a new item to a collection from android. I keep getting a response code of 400: Bad Request. I don't understand what I'm doing wrong and I was hoping someone might be able to help me. Here is the java code.
HttpURLConnection conn = (HttpURLConnection) uri.toURL().openConnection();
conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
conn.setRequestProperty("Accept", "application/json");
conn.setRequestProperty("User-Agent", userAgent);
conn.setChunkedStreamingMode(0);
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.connect();
DataOutputStream out = new DataOutputStream(conn.getOutputStream());
out.write(data.getBytes());
out.flush();
int code = conn.getResponseCode();
String message = conn.getResponseMessage();
conn.disconnect();
The data is a JSON string that looks like the following:
{"Text":"test","RatingValue":3.0,"ReviewID":0,"LocationID":5}
In this case the ReviewID is the primary key.
The URL for the request points to the collection of Ratings. If i paste the same location into my browser, it successfully queries the collection. It looks something like this:
http://localhost/DataService.svc/Ratings

try this :
HttpClient hc = new DefaultHttpClient();
HttpPost hp = new HttpPost("http://localhost/DataService.svc/Ratings");
HttpResponse hr;
JSONObject jo1 = new JSONObject();
joobject.put("Text", "test");
joobject.put("RatingValue", "3.0");
joobject.put("ReviewID", ".0");
joobject.put("LocationID", ".5");
StringEntity se = new StringEntity(joobject.toString(),HTTP.UTF_8);
se.setContentType("application/json");
hp.setEntity(se);
hr = hc.execute(hp);
maybe helpful