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Thread: Client Server Chat application

  1. #1
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    Default Client Server Chat application

    Hi
    I haven't been here in a while and hadn't looked at java for 18 months, up until 3 weeks ago. I have two semesters (16 weeks) of Java behind me which i struggled with. That said I have been handed a java project out of the blue in college to complete(even though we are not doing Java this year).
    For all intensive purposes this is a chat application. I have done the majority of the work on the program and can get it to work opening different instances to communicate with each other on different machines. Thatís Great.
    Effectively i have the client and server running on the same application.
    I open the application and select start server to listen for traffic on a specific port (hard coded in for the moment) associated to the machines IP address. At this point it freezes But wait.
    I can then kick of a second instance of the program and type in the the message i want to send. Hit the send button and it works, kind of(the issue here i understand and can fix). I have a very good idea of what I want to do from here to get it completed.
    My problem is this! I want to be able to use the single instance of the program to start the server and sent messages to itself or, to a different Machine running the same application. This I feel I can do providing I can prevent it freezing when I start up the server. I have tried all sorts of Throwables but still no joy. At this point I have spend the last week just doing trial and error and learning nothing, which is not good.

    I have attached the code below, any help would be greatly appreciated.

    package chat.itb.college;

    import java.awt.EventQueue;
    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import javax.swing.border.EmptyBorder;
    import javax.swing.JButton;
    import java.awt.event.ActionListener;
    import java.awt.event.ActionEvent;
    import java.io.IOException;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    import java.net.SocketException;
    import java.net.UnknownHostException;
    import javax.swing.JLabel;
    import javax.swing.JTextField;
    import javax.swing.SwingConstants;

    public class Chattie extends JFrame{


    private static final long serialVersionUID = 1L;
    protected static final String Double = null;
    private JPanel contentPane;
    private JTextField ipaddress;
    private JTextField portnumber;
    private JTextField conversationtext;
    private JTextField senttext;

    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
    public void run() {
    try {
    Chattie frame = new Chattie();
    frame.setVisible(true);
    } catch (Exception e) {
    e.printStackTrace();
    }
    }
    });
    }

    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    public Chattie() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 590, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    final JButton startserver = new JButton("Start Server");
    startserver.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e)
    {
    DatagramSocket udpServerSocket = null;

    try {
    udpServerSocket = new DatagramSocket(7777);
    } catch (SocketException e2) {
    // TODO Auto-generated catch block
    e2.printStackTrace();
    }

    while(true)
    {
    byte[] receiveData = new byte[1024];
    byte[] sendData = new byte[1024];
    DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
    try {
    udpServerSocket.receive(receivePacket);
    } catch (IOException e1) {
    // TODO Auto-generated catch block
    e1.printStackTrace();
    }
    String clientMessage = (new String(receivePacket.getData())).trim();
    conversationtext.setText("FROM CLIENT:" + clientMessage);
    InetAddress IPAddress = receivePacket.getAddress();
    int port = receivePacket.getPort();
    sendData = ("Received: \""+clientMessage+"\" from "+IPAddress.getHostName()).getBytes();
    DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
    try {
    udpServerSocket.send(sendPacket);
    } catch (IOException e1) {
    // TODO Auto-generated catch block
    e1.printStackTrace();
    }


    }
    }

    });
    startserver.setBounds(12, 39, 110, 25);
    contentPane.add(startserver);

    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    JButton stopbutton = new JButton("Stop Server");
    stopbutton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent arg0) {

    System.exit(0);

    }
    });
    stopbutton.setBounds(12, 77, 110, 25);
    contentPane.add(stopbutton);

    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    JButton send = new JButton("Send");
    send.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent arg0) {

    DatagramSocket udpClientSocket = null;
    try {
    udpClientSocket = new DatagramSocket();
    } catch (SocketException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    InetAddress IPAddress = null;
    try {
    IPAddress = InetAddress.getByName (ipaddress.getText());
    } catch (UnknownHostException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }

    byte[] sendData = new byte[1024];
    byte[] receiveData = new byte[1024];

    String clientRequest = senttext.getText();
    sendData = clientRequest.getBytes();
    DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 7777);

    try {
    udpClientSocket.send(sendPacket);
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
    try {
    udpClientSocket.receive(receivePacket);
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    String serverReply = new String(receivePacket.getData());
    conversationtext.setText("FROM SERVER:" + serverReply.trim());
    udpClientSocket.close();
    }
    });
    send.setBounds(12, 195, 110, 45);
    contentPane.add(send);

    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    JLabel ipLabel = new JLabel("Server Address");
    ipLabel.setBounds(134, 4, 97, 22);
    contentPane.add(ipLabel);
    getContentPane().add (ipLabel);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    ipaddress = new JTextField();
    ipaddress.setText("Enter Address");
    ipaddress.setBounds(237, 4, 102, 22);
    contentPane.add(ipaddress);
    ipaddress.setColumns(10);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    JLabel portLabel = new JLabel("Port Number");
    portLabel.setBounds(351, 4, 80, 22);
    contentPane.add(portLabel);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    portnumber = new JTextField();
    portnumber.setText("Enter Port no.");
    portnumber.setColumns(10);
    portnumber.setBounds(443, 4, 104, 22);
    contentPane.add(portnumber);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    conversationtext = new JTextField();
    conversationtext.setHorizontalAlignment(SwingConst ants.TRAILING);
    conversationtext.setBounds(134, 39, 413, 147);
    contentPane.add(conversationtext);
    conversationtext.setColumns(10);
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    //++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++
    senttext = new JTextField();
    senttext.setColumns(10);
    senttext.setBounds(134, 195, 413, 45);
    contentPane.add(senttext);
    }

    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Client Server Chat application

    Please edit your post and wrap your code with code tags:
    [code=java]
    <YOUR CODE HERE>
    [/code]
    to get highlighting and preserve formatting.

    How can the code be tested?
    If you don't understand my answer, don't ignore it, ask a question.

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