basic socket server in unstable

From:
Robot <robot.dancing@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
23 Apr 2007 03:02:16 -0700
Message-ID:
<1177322536.547443.211310@d57g2000hsg.googlegroups.com>
Hi, I have to use 1.4.1_03 version for development and I am running
into a really weird problem.
I have a server-client program, that receives data from a client and
sends it back to it.

The problem is that, for some reason, this is not what is happening.
It works fine when I only have only one client, but when I have more
than one, the whole hell breaks loose. Can someone please tell me
where I went wrong (other than applying for this job?)

import java.lang.*;
import java.util.*;
import java.io.*;
import java.net.*;

public class sv0 {
    private static final int PORT = 55555;
    private static ServerSocket ss = null;
    private static Hashtable connectInfo = null;

    public static void main(String[] args) {

        try {
            ss = new ServerSocket(PORT);
            while(true) {
                Socket s = ss.accept();
                Thread t = new Thread(new DoClient(s));
                s = null;
                t.start();
            }
        }catch(IOException e) {
            System.out.println("main(IOException):" + e);
        }
    }
}

// client thread
class DoClient implements Runnable, svIF {
    private static Socket s = null; //
    private static ObjectInputStream in = null; //
    private static ObjectOutputStream out = null; //
    private static String ThisDN = null; //

    public DoClient(Socket s) throws IOException {
        System.out.println("---------------Thread
running----------------(DoClient)");
        this.s = s;
        in = new ObjectInputStream(s.getInputStream());
        out = new ObjectOutputStream(s.getOutputStream());
    };

    public void run() {
        MyData d = new MyData();
        try {
            boolean flag = true;
            while(flag) {
                String str = null;
                try {
                    d = (MyData)in.readObject();
                    out.writeObject(d);
                    out.flush();
                } catch (IOException ex) {
                    ex.printStackTrace();
                } catch (ClassNotFoundException ex) {
                    ex.printStackTrace();
                }
            }
            s.close();
        }catch(IOException e) {
        }finally {
            try {
                s.close();
            } catch (IOException ex) {
            }
        }
    }
}
class MyData implements Serializable {
    String a;
    int b;
}

------

Client source code:

import java.awt.Color;
import java.lang.*;
import javax.swing.*;
import java.util.*;
import java.io.*;
import java.net.*;

public class cl0 extends javax.swing.JFrame implements svIF {
    static final String FNAME1 = "c:\\temp\\config1.txt";
    static final String FNAME2 = "c:\\temp\\config2.txt";
    static final String FNAME3 = "c:\\temp\\config3.txt";
    static Socket s = null;
    static ObjectInputStream in = null;
    static ObjectOutputStream out = null;

    static String ip = null;
    static int port = 0;
    static String name = null;

    public cl0() {
        initComponents();
    }

    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">//
GEN-BEGIN:initComponents
    private void initComponents() {
        JbtnsendCmd1 = new javax.swing.JButton();
        JLlogin = new javax.swing.JLabel();
        JtxtMsg = new javax.swing.JTextField();
        JbtnClose = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        JLname = new javax.swing.JLabel();
        JBlogin = new javax.swing.JButton();

        getContentPane().setLayout(new java.awt.GridLayout());

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        JbtnsendCmd1.setText("sendCmd1");
        JbtnsendCmd1.addMouseListener(new
java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                JbtnsendCmd1MouseClicked(evt);
            }
        });
        JbtnsendCmd1.addActionListener(new
java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent
evt) {
                JbtnsendCmd1ActionPerformed(evt);
            }
        });

        getContentPane().add(JbtnsendCmd1);

JLlogin.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        JLlogin.setText("login");

JLlogin.setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);
        getContentPane().add(JLlogin);

        JtxtMsg.setText("test");
        getContentPane().add(JtxtMsg);

        JbtnClose.setText("Close");
        JbtnClose.addActionListener(new
java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent
evt) {
                JbtnCloseActionPerformed(evt);
            }
        });

        getContentPane().add(JbtnClose);

        getContentPane().add(jLabel1);

        JLname.setText("jLabel2");
        getContentPane().add(JLname);

        JBlogin.setText("login");
        JBlogin.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                JBloginMouseClicked(evt);
            }
        });

        getContentPane().add(JBlogin);

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void JBloginMouseClicked(java.awt.event.MouseEvent evt) {//
GEN-FIRST:event_JBloginMouseClicked
        try {
            MyData d = new MyData();
            d.a = name;
            d.b=0;
        out.writeObject(d);
        out.flush();
        }catch(Exception e) {
            System.out.println(e);
        }
    }//GEN-LAST:event_JBloginMouseClicked

    private void JbtnsendCmd1MouseClicked(java.awt.event.MouseEvent
evt) {//GEN-FIRST:event_JbtnsendCmd1MouseClicked
        JOptionPane.showMessageDialog(getContentPane(), "cmd1");
        try {
            MyData d = new MyData();
            d.a = "cmd1-cmd1";
            d.b=0;
            out.writeObject(d);
            out.flush();
            System.out.println("cmd1");
        }catch(Exception e) {

        }
    }//GEN-LAST:event_JbtnsendCmd1MouseClicked

    private void JbtnCloseActionPerformed(java.awt.event.ActionEvent
evt) {//GEN-FIRST:event_JbtnCloseActionPerformed
        try {
            s.close();
        } catch (Exception e) {
        }
        System.exit(0);
    }//GEN-LAST:event_JbtnCloseActionPerformed

    private void
JbtnsendCmd1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-
FIRST:event_JbtnsendCmd1ActionPerformed

    }//GEN-LAST:event_JbtnsendCmd1ActionPerformed

    public static void main(String args[]) {
        cl0 mainFrame = new cl0();
        mainFrame.setVisible(true);

        init(args[0]);

        Thread t = new Thread(new DoClient());
        t.start();
    }

    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton JBlogin;
    public static javax.swing.JLabel JLlogin;
    public static javax.swing.JLabel JLname;
    public static javax.swing.JButton JbtnClose;
    public static javax.swing.JButton JbtnsendCmd1;
    public static javax.swing.JTextField JtxtMsg;
    private javax.swing.JLabel jLabel1;
    // End of variables declaration//GEN-END:variables
    public static void setJLlogin() {
        JLlogin.setForeground(Color.BLUE);
    }
    public static void setJtxt(String msg) {
        JtxtMsg.setText("");
        JtxtMsg.setText(msg);
    }
    public static void setJLname(String name) {
        JLname.setText(name);
    }
    //****************************************************
    //****************************************************
    public static void init(String file_select) {
        String file = null;

        if (file_select.equals("1")) {
            file = FNAME1;
        }else if (file_select.equals("2")){
            file = FNAME2;
        }else {
            file = FNAME3;
        }
        if (readParam(file) == false) {
            return;
        }
        if (connectSv() == false) { return; }
    }
    private static boolean readParam(String fname) {

        try {
            String buff;
            File f = new File(fname);

            BufferedReader br = new BufferedReader(new FileReader(f));
            while ((buff = br.readLine()) != null) {
                StringTokenizer st = new StringTokenizer(buff, ",");
                name = st.nextToken(); //USER NAME
                ip = st.nextToken(); //SERVER IP
                port = Integer.parseInt(st.nextToken()); //SERVER PORT
            }
            //clFrame.setJLname(name);

            return true;
        }catch(Exception e) {
            System.out.println(e);
            e.printStackTrace();
            return false;
        }
    }
    private static boolean connectSv() {
        try {
            s = new Socket(ip, port);
            cl0.out = new ObjectOutputStream(s.getOutputStream());
            cl0.in = new ObjectInputStream(s.getInputStream());

            return true;
        }catch(Exception e) {
            try {
                s.close();
            }catch(IOException e2) {
                System.out.println(e2);
            }
            System.out.println(e);
            e.printStackTrace();
            return false;
        }
    }
}
//****************************************************
//Thread
//****************************************************
class DoClient implements Runnable {
    MyData d = null;
    public void run() {

        while(cl0.s != null) {
            String str = null;
            try {
                d = (MyData)cl0.in.readObject();
                cl0.setJtxt(d.a);
            } catch (IOException ex) {
                ex.printStackTrace();
            } catch (ClassNotFoundException ex) {
                ex.printStackTrace();
            }

        }
    }
}
class MyData implements Serializable {
    String a;
    int b;
}

Thanks!
Thanks!

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