Error java.net.ProtocolException: Cannot write output after reading input.

[wishknew]

Hello guys,

I've got stuck with making a post connection using https.
Here is my code:

HTTPS Client

public void run() {
        HttpsURLConnection httpsConnection = null;
        int responseCode=0;
        String address = "https://" + config.getHTTPSServerAddress();
        SSLContext sc = null;
        String encodedContent;

        prepareSecureConnection(sc);

        httpsConnection = openConnection(address, httpsConnection, responseCode);
        printResponseContent(httpsConnection);
        httpsConnection.disconnect();

        encodedContent = getEncodedContent();
        writeEncodedContent(httpsConnection, encodedContent);//error here
    }

    private void writeEncodedContent(HttpsURLConnection httpsConnection, String encodedContent) {
        OutputStreamWriter writer;
        try {
             outputStream = httpsConnection.getOutputStream();
             writer = new OutputStreamWriter(outputStream);
             writer.write(encodedContent);
             writer.flush();
             outputStream.close();

        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private String getEncodedContent() {
        String content = "";
        int data;
        try {
            inputStream = clientIFX.getInputStream();
            data = inputStream.read();
            while (data != -1) {
                content += (char)data;
                data = inputStream.read();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        if (content.equals("")) {
            return "";
        }
        else {
            return Base64.encodeBytes(content.getBytes(), Base64.GZIP);
        }
    }

    private void printResponseContent(HttpsURLConnection connection) {
        StringBuffer buffer;
        InputStream input;
        BufferedReader dataInput;
        String line;
        String responseContent = "";
        try {
            buffer = new StringBuffer();
            input = connection.getInputStream();
            dataInput = new BufferedReader(new InputStreamReader(input));
            while ((line = dataInput.readLine()) != null) {
                buffer.append(line);
                buffer.append('\n');
            }
            input.close();
            responseContent = (String) buffer.toString().trim();
        } catch (Exception e) {
            System.err.println(e);
        }
        System.out.println(responseContent);

    }

    private HttpsURLConnection openConnection(String address, HttpsURLConnection connection, int responseCode) {
        URL url;
        try {
            url = new URL(address);
            connection = (HttpsURLConnection) url.openConnection();

            connection.setDoInput(true);
            connection.setDoOutput(true);

            responseCode = connection.getResponseCode();

        } catch (Exception e) {
            System.err.println("Ooops : " + e + " (Response code is " + responseCode + ")");
        }
        return connection;
    }

    private void prepareSecureConnection(SSLContext sc) {
        try {
            sc = SSLContext.getInstance("SSLv3");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        TrustManager[] tma = {this};
        try {
            sc.init(null, tma, null);
        } catch (KeyManagementException e) {
            e.printStackTrace();
        }
        SSLSocketFactory ssf = sc.getSocketFactory();
        HttpsURLConnection.setDefaultSSLSocketFactory(ssf);
        HttpsURLConnection.setDefaultHostnameVerifier(hv);
    }

The error was:
java.net.ProtocolException: Cannot write output after reading input.
at sun.net.www.protocol.http.HttpURLConnection.getOut putStream(HttpURLConnection.java:565)
at sun.net.www.protocol.https.HttpsURLConnectionImpl. getOutputStream(DashoA12275)
at IFXCompressor.writeEncodedContent(IFXCompressor.ja va:55)
at IFXCompressor.run(IFXCompressor.java:49)


My question is how to post a message using HttpsURLConnection? (without doing any get at all)

Thank you,


WishKnew

[wishknew]

After changing the writeEncodedContent method, I can get rid the error off from my program.

The changes are:

private void writeEncodedContent(String encodedContent) {
        DataOutputStream writer;
        HttpsURLConnection connection = null;
        encodedContent = "content=" + encodedContent;

        try {
            connection = (HttpsURLConnection) new URL("https://10.8.8.40").openConnection();
            connection.setRequestProperty("User-Agent", "IFXClient");
            connection.setDoOutput(true);
            connection.setUseCaches(false);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "text/plain");
            connection.setRequestProperty("Content-Length", "" + encodedContent.length());

            connection.connect();

        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
             writer = new DataOutputStream(connection.getOutputStream());
             writer.writeBytes(encodedContent);
             writer.flush();
             writer.close();

        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

And the server code for handling the request is :

public ProcessConnection(Socket s) { // constructor
      client = s;
      try {
         is = new BufferedReader(new InputStreamReader
           (client.getInputStream()));
         os = new DataOutputStream(client.getOutputStream());
      } catch (IOException e) {
         System.out.println("Exception: "+e.getMessage());
      }

      System.out.println("Processing connection from " + s.getInetAddress().toString());

      this.start(); // Thread starts here...this start() will call run()
   }

   public void run() {
      try {
         // get a request and parse it.
            
         String request = is.readLine();
         System.out.println( "Request: "+request );
       } catch (Exception e) {
         System.out.println("Exception: " +
           e.getMessage());
      } 
   }

The error is gone, but the request become NULL when I try to post. I don't have any problem for GET message.

Please advice.

Thank you in advance.

Wisnu (WishKnew)

[Belisarius]

What does the output usually look like for a GET?

[wishknew]

What does the output usually look like for a GET?

Actually, I just open its connection (default to index.html), get the InputStream, and read from it. I've got full HTML code from the server.

private void printResponseContent(HttpsURLConnection connection) {
        StringBuffer buffer;
        InputStream input;
        BufferedReader dataInput;
        String line;
        String responseContent = "";
        try {
            buffer = new StringBuffer();
            input = connection.getInputStream();
            dataInput = new BufferedReader(new InputStreamReader(input));
            while ((line = dataInput.readLine()) != null) {
                buffer.append(line);
                buffer.append('\n');
            }
            input.close();
            responseContent = (String) buffer.toString().trim();
        } catch (Exception e) {
            System.err.println(e);
        }
        System.out.println(responseContent);
    }

I have copy the information from http://www.dcs.shef.ac.uk/~fabio/COM...web%20MINI.pdf
and http://www.javaworld.com/javaworld/j...323-traps.html as basic of my code.

I will be glad if one of you can give me a simple httpSServer class which print any request and a httpClient (which connect to httpsUrlConnection) and doing a simple POST.

Thank you,


WishKnew

[sde]

here is some code i use to consume a web service using GET, but not post. sorry it's not much help. good luck.

URL productURLRequest;
BufferedReader in;
String productURLResponse;
  
// read url
productURLRequest = new URL("http://www.myserver.com/lookup.php?ProdID=someproduct");
in = new BufferedReader(new InputStreamReader(productURLRequest.openStream()));

if((productURLResponse = in.readLine()) == null)
  productURLResponse = "0";

in.close();