CODEWITHSUNDEEP
javasocketshttp
lapots
lapots

Reputation: 13395

unknown host exception when I try to send request

I'm trying to check whether several pors are open and if 80 port is open - send http request and then show result in console. Every port is checked in his own thread.

I send requests like this

public static void send(Socket sock, String host) throws IOException{
    PrintWriter pw = new PrintWriter(sock.getOutputStream());
    pw.println("GET / HTTP/1.1");
    pw.println("Host: " + host);
    pw.println("");
    pw.flush();
}

In class TCPClient I use it and return result as bytes and then show it console.

    try {
        sock = new Socket(host, port);
        System.out.println("port " + port + " is in use");
        // send request
        HttpSender.send(sock, host);
        BufferedReader bf = new BufferedReader(new InputStreamReader(sock.getInputStream()));
        StringBuffer response = new StringBuffer(); 
        String line = "";
        while((line = bf.readLine()) != null) {
          response.append(line);
          response.append('\r');
        }
        bf.close();
        return String.valueOf(response).getBytes(); // in method run I show it
    } catch (SocketException e) {
        return ("port " + port + " is free").getBytes();
    }

I create pool of threads for port checking. 

public class ThreadPool {

private static int MAX_THREADS = 5;
private static String DESTINATION = "http://stackoverflow.com/";
private ExecutorService es = null;

public ThreadPool() {
    es = Executors.newFixedThreadPool(MAX_THREADS);
}

public void perform(int start, int end) throws UnknownHostException {
    for (int i = start; i <= end; i++) {
        Runnable req = new TCPClient(DESTINATION, i);
        es.execute(req);
    }
    es.shutdown();
    while (!es.isTerminated()) {
    }
    ;
    System.out.println("all ports checked!");
}

}

When I set destination as www.stackoverflow.com and got document with text that it was moved permanently to http://stackoverflow.com/. When I set this destination - I've got UnknownhostException.

Where is the problem?

Upvotes: 0

Views: 280

Answers (1)

admdrew
admdrew

Reputation: 3863

Have you tried private static String DESTINATION = "stackoverflow.com";? The string "http://stackoverflow.com" isn't a hostname, it's a URL.

Upvotes: 2

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