Desktop client web server communication

Question

I am doing client server communication. I got both connected via URLConnection classes.

Now I am trying to send log in information to server, Server will check if information is correct else it will ask me to log in again and for this scenario lets assume log in was unsuccessful. But after getting response from server when I try again to send log in information I am getting

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

Here is my code:

URL url = new URL(uniRL);

java.net.URLConnection connection = url.openConnection();
connection.setAllowUserInteraction(true);
connection.setDoOutput(true);

while(true){
    System.out.println("Enter 1-login , 2-Exit");
useroption = input.nextLine();
numOption = Integer.parseInt(useroption);
if( numOption == 1){
    OutputStreamWriter writer = new OutputStreamWriter(
            connection.getOutputStream());
    user_login = login();
    writer.write(user_login[0]+"@");
    writer.write(user_login[1]);
    writer.flush();
    //out.close();
    BufferedReader in = new BufferedReader(
            new InputStreamReader(
                    connection.getInputStream()));
    while ((tempString = in.readLine()) != null) {
        decodedString = tempString;
        //System.out.println(decodedString);
        //System.out.println(decodedString.equalsIgnoreCase("unknown user"));
    }
    in.close();
    if((decodedString.equalsIgnoreCase("unknown user"))){continue;}
    else{break;}
}

Which is the line where you are getting this exception ? Posting the exception trace would help. — Santosh, Sep 19 '12 at 10:30
I am getting exception when the loop goes for its second iteration. and tries to write something for second time. — Haseeb Wali, Sep 20 '12 at 05:50

score 0 · Answer 1 · answered Sep 19 '12 at 10:10

0

When you call in.close(), you're actually closing the stream used by the URL connection. You'd need to call url.openConnection() again to re-open the stream...

answered Sep 19 '12 at 10:10

MadProgrammer

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brother thanks for help i tried it without in.close(). it is still not working. i am getting same exception.... – Haseeb Wali Sep 19 '12 at 10:15
I'm not sure why you've chosen `URLConnection` to do this, I'd probably do a straight `Socket` connection, personally – MadProgrammer Sep 19 '12 at 20:04
can you give me some good example/link for using socket with desktop(client) and web server? It will be really helpful..thankyou – Haseeb Wali Sep 19 '12 at 21:38
@HaseebWali What protocol are you using?? HTTP?? – MadProgrammer Sep 19 '12 at 23:01

Desktop client web server communication

1 Answers1