Send UTF-8 chars via HttpURLConnection failing

Question

I have spent half Sunday on this now I need help:

I want to send a String including special chars UTF-8 encoded to a server using Java HttpURLConnection. The correct encoding of the chars fails.

Example:

strToSend: ä ù €
strUrlEncoded: %C3%A4+%C3%B9+%E2%82%AC
strReceived:ä ù â¬

My code:

        urlConnection = (HttpURLConnection) new URL("http://localhost:8080/NetworkingServer/ServerServlet").openConnection();
        urlConnection.setUseCaches(false);
        urlConnection.setDoOutput(true); // Triggers POST.
        urlConnection.setRequestProperty("accept-charset", "UTF-8");
        urlConnection.setRequestProperty("content-type", "application/x-www-form-urlencoded");

        String strToSend = "ä ù €";
        System.out.println("strToSend: " + strToSend);
        String strUrlEncoded = URLEncoder.encode(strToSend, "UTF-8");
        System.out.println("strUrlEncoded: " + strUrlEncoded);

        OutputStreamWriter writer = new OutputStreamWriter(urlConnection.getOutputStream(), "UTF-8");
        writer.write(String.format("content=%s", strUrlEncoded));
        writer.close();

Any ideas?

Solution

You need to set the encoding in your Content-Type header.

Set it to "application/x-www-form-urlencoded; charset=utf-8". Currently you only set the accept-charset - this tells the server what to send back.