자바 멀티서버 기본소스

MultiChatServer.java

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

public class MultiChatServer
{

 public static void main(String[] args)
 {
  try
  {
   ServerSocket serverSoc = new ServerSocket(10001);
   System.out.println("접속을 기다립니다.");
   HashMap hm = new HashMap();
   while(true)
   {
    Socket sock = serverSoc.accept();
    ChatThread chatthread = new ChatThread(sock,hm);
    chatthread.start();
   }
  }
  catch (Exception ex)
  {
   System.out.println(ex);
  }
  System.out.println("Hello World!");
 }
}

class ChatThread extends Thread
{
 private Socket socket;
 private String id;
 private BufferedReader br;
 private PrintWriter pw;
 private HashMap hm;
 private boolean initFlag = false;
 public ChatThread(Socket socket,HashMap hm)
 {
  this.socket = socket;
  this.hm = hm;
 
  try
  {
   pw = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
   br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
   //System.out.println("11111");
   id=br.readLine();
   //System.out.println("22222");
   broadcast(id +"님이 접속했습니다.");
   System.out.println("접속한 사용자의 아이디는 "+ id +"입니다.");
   
   synchronized(hm)
   {
    hm.put(this.id,pw);
   }
   
   initFlag = true;
  }
  catch (Exception ex)
  {
   //System.out.println("111111111");
   ex.printStackTrace();
  }
 }
 public void run()
 {
  try
  {
   String line = null;
   System.out.println("1111111111");
   while((line = br.readLine()) != null)
   {
    broadcast(id + ":" +line);
   }
   System.out.println("22222222222");
  }
  catch (Exception ex)
  {
   //System.out.println("2222222");
   ex.printStackTrace();
  }
  finally
  {
   synchronized(hm)
   {
    hm.remove(id);
   }
   try
   {
    if(socket!=null)
     socket.close(); 
   }
   catch (Exception ex)
   {
   }
  }

 }
 public void broadcast(String msg)
 {
  synchronized(hm)
  {
   Collection col = hm.values();
   Iterator iter = col.iterator();
   while(iter.hasNext())
   {
    PrintWriter pw = (PrintWriter)iter.next();
    pw.println(msg);
    pw.flush();
   }
  }
 }
}