I'm trying to set up TCP communications between two machines, but for now (in the initial/testing phase) am using localhost.
Can anybody see why I'm getting these msgs in the Console (all I'm doing is running the app, not even pressing the button:
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.jcp.tds.RTTCPSortSimMain.setUpNetworking(RTTCP SortSimMain.java:104)
at com.jcp.tds.RTTCPSortSimMain.go(RTTCPSortSimMain.j ava:91)
at com.jcp.tds.RTTCPSortSimMain.main(RTTCPSortSimMain .java:34)
Exception in thread "Thread-2" java.lang.NullPointerException
at com.jcp.tds.RTTCPSortSimMain$IncomingReader.run(RT TCPSortSimMain.java:138)
at java.lang.Thread.run(Unknown Source)
with the following code (which is basically ripped straight from "Head First Java"):
?public class RTTCPSortSimMain { ... BufferedReader reader; PrintWriter writer; Socket sock; public static void main(String[] args) { new RTTCPSortSimMain().go(); } public void go() { ... (GUI code) JButton sendButton = new JButton("Send and Receive"); sendButton.addActionListener(new SendButtonListener()); tfHost = new JTextField(16); tfHost.setText("127.0.0.1"); tfPort = new JTextField(4); tfPort.setText("4211"); ... (more GUI code) setUpNetworking(); Thread readerThread = new Thread(new IncomingReader()); readerThread.start(); ... (more GUI code) } private void setUpNetworking() { try { // for testing (localhost) sock = new Socket("127.0.0.1", 5000); InputStreamReader streamReader = new InputStreamReader(sock.getInputStream()); reader = new BufferedReader(streamReader); writer = new PrintWriter(sock.getOutputStream()); System.out.println("networking established"); } catch(IOException ex) { ex.printStackTrace(); } } public class SendButtonListener implements ActionListener { @Override public void actionPerformed(ActionEvent ev) { try { writer.println(outgoing.getText()); writer.flush(); } catch (Exception ex) { ex.printStackTrace(); } outgoing.setText(""); outgoing.requestFocus(); } } class IncomingReader implements Runnable { @Override public void run() { String message; try { while ((message = reader.readLine()) != null) { System.out.println("client read " + message); incoming.append(message + "\n"); } } catch (IOException ex) { ex.printStackTrace(); } } } }