Java new socket connection refused

Question

I'm trying to write a simple proxy server, and I found this code online and I just want to try to run it see if it works, but when it creates a new socket, it got an ConnectException that says Connect refused. I'm using 'localhost' as the host and I tried several different ports but nothing works. What's the problem here, is it the code or my machine?

public static void runServer(String host, int remotePort, int localPort) throws IOException {

    // Create the socket for listening connections
    ServerSocket mySocket = new ServerSocket(localPort);

    final byte[] request = new byte[1024];
    byte[] reply = new byte[4096];

    while (true) {
        Socket client = null, server = null;

        try {
            client = mySocket.accept();

            final InputStream streamFromClient = client.getInputStream();
            final OutputStream streamToClient = client.getOutputStream();

            try {
                server = new Socket(host, remotePort);
            } catch (IOException e) {
                PrintWriter out = new PrintWriter(streamToClient);
                out.print("Proxy server cannot connect to " + host + ":"
                + remotePort + ":\n" + e + "\n");
                out.flush();
                client.close();
                continue;
            }

            final InputStream streamFromServer = server.getInputStream();
            final OutputStream streamToServer = server.getOutputStream();

            Thread t = new Thread() {
                public void run() {
                    int bytesRead;
                    try {
                        while ((bytesRead = streamFromClient.read(request)) != -1) {
                            streamToServer.write(request, 0, bytesRead);
                            streamToServer.flush();
                        }
                    } catch (IOException e) {
                    }
                }
            };

            t.start();

            int bytesRead;
            try {
                while ((bytesRead = streamFromServer.read(reply)) != -1) {
                    streamToClient.write(reply, 0, bytesRead);
                    streamToClient.flush();
                }
            } catch (IOException e) {
            }
            streamToClient.close();

        } catch (IOException e) {
            System.err.println(e);
        } finally {
            try {
                if (server != null)
                    server.close();
                if (client != null)
                    client.close();
            } catch (IOException e) {
            }
        }
    }

score 0 · Answer 1 · answered Jan 31 '16 at 08:55

0

'Connection refused' means exactly one thing: nothing was listening at the IP:port you tried to connect to. So it was wrong. The solution is to get it right, or to start the server if it hadn't been started.

answered Jan 31 '16 at 08:55

user207421

305,947
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I'm using localhost, so I don't know what you mean by 'start the server if it hadn't been started'. What exactly do I need to do? – Shawn Zhong Jan 31 '16 at 17:37
How would I know? It's your server. I don't find anything unclear about the text you quoted. – user207421 Feb 01 '16 at 05:36

score -1 · Answer 2 · edited May 23 '17 at 11:52

-1

You need to set timeout while reading data from socket, there is an example available here

edited May 23 '17 at 11:52

Community

1
1

answered Jan 31 '16 at 07:34

Abhijeet

8,561
5
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Rubbish. You can't even set a timeout, let alone read anything from a socket, let alone get a timeout exception, until you have a socket, and OP doesn't have a socket: he has 'connection refused'. The answer you cite is (a) about UDP and (b) wrong. – user207421 Feb 01 '16 at 08:59

Java new socket connection refused

2 Answers2