//聊天室的客戶端 
import java.applet.*; 
import java.awt.*; 
import java.io.*; 
import java.net.*; 
import java.awt.event.*; 
public class ChatClient extends Applet{ 
protected boolean loggedIn;//登入狀態 
protected Frame cp;//聊天室框架 
protected static int PORTNUM=7777; //缺省端口號7777 
protected int port;//實際端口號 
protected Socket sock; 
protected BufferedReader is;//用于從sock讀取數據的BufferedReader 
protected PrintWriter pw;//用于向sock寫入數據的PrintWriter 
protected TextField tf;//用于輸入的TextField 
protected TextArea ta;//用于顯示對話的TextArea 
protected Button lib;//登入按鈕 
protected Button lob;//登出的按鈕 
final static String TITLE ="Chatroom applet>>>>>>>>>>>>>>>>>>>>>>>>"; 
protected String paintMessage;//發表的消息 
public ChatParameter Chat; 
public void init(){ 
paintMessage="正在生成聊天窗口"; 
repaint(); 
cp=new Frame(TITLE); 
cp.setLayout(new BorderLayout()); 
String portNum=getParameter("port");//呢個參數勿太明 
port=PORTNUM; 
if (portNum!=null) //書上是portNum==null,十分有問題 
port=Integer.parseInt(portNum); 
//CGI 
ta=new TextArea(14,80); 
ta.setEditable(false);//read only attribute 
ta.setFont(new Font("Monospaced",Font.PLAIN,11)); 
cp.add(BorderLayout.NORTH,ta); 
Panel p=new Panel(); 
Button b; 
//for login button 
p.add(lib=new Button("Login")); 
lib.setEnabled(true); 
lib.requestFocus(); 
lib.addActionListener(new ActionListener() { 
public void actionPerformed(ActionEvent e){ 
login(); 
lib.setEnabled(false); 
lob.setEnabled(true); 
tf.requestFocus();//將鍵盤輸入鎖定再右邊的文本框中 
} 
}); 
//for logout button 
p.add(lob=new Button ("Logout")); 
lob.setEnabled(false); 
lob.addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e){ 
logout(); 
lib.setEnabled(true); 
lob.setEnabled(false); 
lib.requestFocus(); 
} 
}); 
p.add(new Label ("輸入消息:")); 
tf=new TextField(40); 
tf.addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e){ 
if(loggedIn){ 
//pw.println(Chat.CMD_BCAST+tf.getText());//Chat.CMD....是咩野來? 
int j=tf.getText().indexOf(":"); 
if(j>0) pw.println(Chat.CMD_MESG+tf.getText()); 
else 
pw.println(Chat.CMD_BCAST+tf.getText()); 
tf.setText("");//勿使用flush()? 
} 
} 
}); 
p.add(tf); 
cp.add(BorderLayout.SOUTH,p); 
cp.addWindowListener(new WindowAdapter(){ 
public void windowClosing(WindowEvent e){ 
//如果執行了setVisible或者dispose,關閉窗口 
ChatClient.this.cp.setVisible(false); 
ChatClient.this.cp.dispose(); 
logout(); 
} 
}); 
cp.pack();//勿明白有咩用? 
//將Frame cp放在中間 
Dimension us=cp.getSize(), 
them=Toolkit.getDefaultToolkit().getScreenSize(); 
int newX=(them.width-us.width)/2; 
int newY=(them.height-us.height)/2; 
cp.setLocation(newX,newY); 
cp.setVisible(true); 
paintMessage="Window should now be visible"; 
repaint(); 
} 
//登錄聊天室 
public void login(){ 
if(loggedIn) return; 
try{ 
sock=new Socket(getCodeBase().getHost(),port); 
is=new BufferedReader(new InputStreamReader(sock.getInputStream())); 
pw=new PrintWriter(sock.getOutputStream(),true); 
}catch(IOException e){ 
showStatus("Can't get socket: "+e); 
cp.add(new Label("Can't get socket: "+e)); 
return;} 
//構造并且啟動讀入器,從服務器讀取數據,輸出到文本框中 
//這里,長成一個線程來避免鎖住資源(lockups) 
new Thread (new Runnable(){ 
public void run(){ 
String line; 
try{ 
while(loggedIn &&((line=is.readLine())!=null)) 
ta.appendText(line+"\n"); 
}catch(IOException e){ 
showStatus("我的天啊,掉線了也!!!!"); 
return; 
} 
} 
}).start(); 
//假定登錄(其實只是打印相關信息,并沒有真正登錄) 
// pw.println(Chat.CMD_LOGIN+"AppletUser"); 
pw.println(Chat.CMD_LOGIN+"AppletUser"); 
loggedIn =true; 

} 
//模仿退出的代碼 
public void logout(){ 
if(!loggedIn) 
return; 
loggedIn=false; 
try{ 
if(sock!=null) 
sock.close(); 
}catch(IOException ign){ 
// 異常處理哦 
} 
} 
//沒有設置stop的方法,即使從瀏覽器跳到另外一個網頁的時候 
//聊天程序還可以繼續運行 
public void paint(Graphics g){ 
Dimension d=getSize(); 
int h=d.height; 
int w=d.width; 
g.fillRect(0,0,w,2); 
g.setColor(Color.black); 
g.drawString(paintMessage,10,(h/2)-5); 
} 
} 



聊天室服務器端 
import java.net.*; 
import java.io.*; 
import java.util.*; 

public class ChatServer{ 
//聊天室管理員ID 
protected final static String CHATMASTER_ID="ChatMaster"; 
//系統信息的分隔符 
protected final static String SEP=": "; 
//服務器的Socket 
protected ServerSocket servSock; 
//當前客戶端列表 
protected ArrayList clients; 
//調試標記 
protected boolean DEBUG=false; 
public ChatParameter Chat; 

//主方法構造一個ChatServer,沒有返回值 
public static void main(String[] argv){ 
System.out.println("Chat server0.1 starting>>>>>>>>>>>>>>>>"); 
ChatServer w=new ChatServer(); 
w.runServer(); 
System.out.println("***ERROR*** Chat server0.1 quitting"); 

} 


//構造和運行一個聊天服務 
ChatServer(){ 
Chat=new ChatParameter(); 
clients=new ArrayList(); 
try{ 
servSock=new ServerSocket(7777);//實有問題拉,不過可能是他自己定義既一個class. 
System.out.println("Chat Server0.1 listening on port:"+7777); 
}catch(Exception e){ 
log("IO Exception in ChatServer.<init>"); 
System.exit(0); 
} 
} 

public void runServer(){ 
try{ 
while(true){ 
Socket us=servSock.accept(); 
String hostName=us.getInetAddress().getHostName(); 
System.out.println("Accpeted from "+hostName); 
//一個處理的線程 
ChatHandler cl=new ChatHandler(us,hostName); 
synchronized(clients){ 
clients.add(cl); 
cl.start(); 
if(clients.size()==1) 
cl.send(CHATMASTER_ID,"Welcome!You are the first one here"); 
else{ 
cl.send(CHATMASTER_ID,"Welcome!You are the latest of"+ 
clients.size()+" users."); 
} 
} 
} 
}catch(Exception e){ 
log("IO Exception in runServer:"+e); 
System.exit(0); 
} 
} 


protected void log(String s){ 
System.out.println(s); 
} 


//處理會話的內部的類 
protected class ChatHandler extends Thread { 
//客戶端scoket 
protected Socket clientSock; 
//讀取socket的BufferedReader 
protected BufferedReader is ; 
//在socket 上發送信息行的PrintWriter 
protected PrintWriter pw; 
//客戶端出主機 
protected String clientIP; 
//句柄 
protected String login; 

public ChatHandler (Socket sock,String clnt)throws IOException { 
clientSock=sock; 
clientIP=clnt; 
is=new BufferedReader( 
new InputStreamReader(sock.getInputStream())); 
pw=new PrintWriter (sock.getOutputStream(),true); 

} 

//每一個ChatHandler是一個線程,下面的是他的run()方法 
//用于處理會話 
public void run(){ 
String line; 

try{ 
while((line=is.readLine())!=null){ 
char c=line.charAt(0);//我頂你老母啊 ,果只Chat.CMD咩xx冇定義 撲啊///!!! 
line=line.substring(1); 
switch(c){ 
//case Chat.CMD_LOGIN: 
case 'l': 
if(!Chat.isValidLoginName(line)){ 
send(CHATMASTER_ID,"LOGIN"+line+"invalid"); 
log("LOGIN INVALID from:"+clientIP); 
continue; 
} 

login=line; 
broadcast(CHATMASTER_ID,login+" joins us,for a total of"+ 
clients.size()+" users"); 
break; 

// case Chat.CMD_MESG: 
case 'm': 
if(login==null){ 
send(CHATMASTER_ID,"please login first"); 
continue; 
} 

int where =line.indexOf(Chat.SEPARATOR); 
String recip=line.substring(0,where); 
String mesg=line.substring (where+1); 
log("MESG: "+login+"--->"+recip+": "+mesg); 
ChatHandler cl=lookup(recip); 
if(cl==null) 
psend(CHATMASTER_ID,recip+"not logged in."); 
else 
cl.psend(login,mesg); 

break; 


//case Chat.CMD_QUIT: 
case 'q': 
broadcast(CHATMASTER_ID,"Goodbye to "+login+"@"+clientIP); 
close(); 
return;//ChatHandler結束 


// case Chat.CMD_BCAST: 
case 'b': 
if(login!=null) 
broadcast(login,line); 
else 
log("B<L FROM"+clientIP); 
break; 

default: 
log("Unknow cmd"+c+"from"+login+"@"+clientIP); 
} 
} 
}catch(IOException e){ 
log("IO Exception :"+e); 
}finally{ 
//sock 結束,我們完成了 
//還不能發送再見的消息 
//得有簡單的基于命令的協議才行 
System.out.println(login+SEP+"All Done"); 
synchronized(clients){ 
clients.remove(this); 
if(clients.size()==0){ 
System.out.println(CHATMASTER_ID+SEP+ 
"I'm so lonely I could cry>>>>>"); 
}else if(clients.size()==1){ 
ChatHandler last=(ChatHandler)clients.get(0); 
last.send(CHATMASTER_ID,"Hey,you are talking to yourself again"); 
} 
else{ 
broadcast(CHATMASTER_ID,"There are now"+clients.size()+" users"); 
} 
} 
} 
} 
protected void close(){ 
if(clientSock==null){ 
log("close when not open"); 
return; 
} 
try{ 
clientSock.close(); 
clientSock=null; 
}catch(IOException e){ 
log("Failure during close to "+clientIP); 
} 
} 
//發送一條消息給用戶 
public void send(String sender,String mesg){ 
pw.println(sender+SEP+"*>"+mesg); 
} 
//發送私有的消息 
protected void psend(String sender ,String msg){ 
send("<*"+sender+"*>",msg); 
} 
//發送一條消息給所有的用戶 
public void broadcast (String sender,String mesg){ 
System.out.println("Broadcasting"+sender+SEP+mesg); 
for(int i=0;i<clients.size();i++){ 
ChatHandler sib=(ChatHandler)clients.get(i); 
if(DEBUG) 
System.out.println("Sending to"+sib); 
sib.send(sender,mesg); 
} 
if(DEBUG) System.out.println("Done broadcast"); 
} 
protected ChatHandler lookup(String nick){ 
synchronized(clients){ 
for(int i=0;i<clients.size();i++){ 
ChatHandler cl=(ChatHandler)clients.get(i); 
if(cl.login.equals(nick)) 
return cl; 
} 
} 
return null; 
} 
//將ChatHandler對象轉換成一個字符串 
public String toString(){ 
return "ChatHandler["+login+"]"; 
} 
} 
} 



public class ChatParameter { 
public static final char CMD_BCAST='b'; 
public static final char CMD_LOGIN='l'; 
public static final char CMD_MESG='m'; 
public static final char CMD_QUIT='q'; 
public static final char SEPARATOR=':';//????? 
public static final int PORTNUM=7777; 
public boolean isValidLoginName(String line){ 
if (line.equals("CHATMASTER_ID")) 
return false; 
return true; 
} 
public void main(String[] argv){ 
} 
}