Java程序（聊天）

import java.io.*; 
public class ServerClass{ 
public static void main(String args[]){ 
int i=0; 
try{ 
ServerSocket ss=new ServerSocket(2345);//为该服务器开设一个端口，该端口供客户机程序来访问。 
System.out.println("服务器启动......"); 
while(true){ 
Socket sock=ss.accept();//sock对象接收客户机的连接请求，程序运行到这里将处于等待状态。 
i++; 
System.out.println("接受连接请求"+i); 
PrintStream out=new PrintStream(sock.getOutputStream());//获得输出流 
out.println("你好"); 
out.close(); 
sock.close(); 
} 
}catch(IOException e){ 
System.out.println(e); 
} 
} 
} 

import java.io.*; 
import java.net.*; 
public class AClient{ 
public static void main(String args[]){ 
try{ 
Socket sock=new Socket("127.0.0.1",2345);//根据具体的（正在用的机器的）IP和端口，创建一个Socket对象 
BufferedReader in=new BufferedReader(new InputStreamReader(sock.getInputStream()));//获得输入流。 
String s=in.readLine();//从输入流读入一行内容。 
System.out.println(s);//打印出 
in.close(); 
}catch(IOException e){} 
} 
} 

import java.io.*; 
import java.net.*; 
import javax.swing.*; 
import java.awt.event.*; 
import java.awt.*; 
/** 
用户界面ServerUI 
*/ 
public class ServerUI extends JFrame{ 
JTextArea mainArea; 
JTextArea sendArea; 
JTextField indexArea; 
SvrCom server; 
public void setServer( SvrCom server ) 
{ this.server = server; } 
public ServerUI() 
{ 
super("服务器端"); 
Container contain = getContentPane(); 
contain.setLayout( new BorderLayout() ); 
mainArea = new JTextArea(); 
JScrollPane mainAreaP = new JScrollPane( mainArea ); 
JPanel panel = new JPanel(); 
panel.setLayout( new BorderLayout() ); 
sendArea = new JTextArea(3, 8); 
JButton sendBtn = new JButton("发送"); 
sendBtn.addActionListener( new ActionListener()//注册动作监听器 
{ 
public void actionPerformed(ActionEvent ae) 
{ 
server.sendMsg(sendArea.getText());//把信息传递到客户端 
mainArea.append( "【服务器】" + sendArea.getText() + "\n" );//把信息显示在服务器的聊天记录区域 
sendArea.setText(""); 
} 
} 
); 
JPanel tmpPanel = new JPanel(); 
indexArea = new JTextField(2); 
indexArea.setText("0"); 
tmpPanel.add( sendBtn ); 
tmpPanel.add( indexArea ); 
panel.add( tmpPanel, BorderLayout.EAST ); 
panel.add(sendArea, BorderLayout.CENTER ); 
contain.add( mainAreaP, BorderLayout.CENTER ); 
contain.add( panel, BorderLayout.SOUTH ); 
setSize( 500, 300); 
setVisible( true ); 
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
} 
public static void main(String[] args) 
{ 
ServerUI ui = new ServerUI(); 
SvrCom server = new SvrCom( ui );//创建并启动网络通讯线程，准备接受客户端数据包 
} 
} 

/** 
通讯类SvrCom负责守候数据到来 
*/ 
class SvrCom extends Thread//网络通讯类 
{ 
Socket client; 
ServerSocket soc; 
BufferedReader in; 
PrintWriter out; 
ServerUI ui; 
// ChatServer server; 

public SvrCom( ServerUI ui ){ //初始化SvrCom类 
this.ui = ui; 
ui.setServer( this ); 
try { 
soc = new ServerSocket(6666 ); //开设服务器端口6666 
System.out.println( "启动服务器成功，等待端口号：6666" ); 
client = soc.accept();//当客户机请求连接时，创建一条链接 
System.out.println( "连接成功！来自" + client.toString() ); 
in = new BufferedReader( new InputStreamReader( client.getInputStream()) ); 
out = new PrintWriter( client.getOutputStream() , true); 
} catch( Exception ex ) { System.out.println( ex ); } 
start(); 
} 
public void run () {// 用于监听客户端发送来的信息 
String msg = ""; 
while( true ) 
{ 
try { 
msg = in.readLine();//从in对象上读数据信息 
} 
catch( SocketException ex ) { 
System.out.println(ex); 
break; 
} 
catch( Exception ex ) { System.out.println(ex); } 
if( msg!=null && msg.trim()!="" ) 
{ 
System.out.println(">>" + msg ); 
ui.mainArea.append( msg + "\n" ); 
} 
} 
} 
public void sendMsg( String msg ) {// 用于发送信息 
try { 
out.println("【服务器】" + msg );//把信息写入输出流 
} 
catch(Exception e) { 
System.out.println( e ); 
} 
} 
} 

import java.io.*; 
import java.net.*; 
import javax.swing.*; 
import java.awt.event.*; 
import java.awt.*; 
/** 
用户界面ClientUI 
*/ 
public class ClientUI extends JFrame 
{ 
JTextArea mainArea; 
JTextArea sendArea; 
ChatClient client; 
JTextField ipArea; 
JButton btnLink; 
public void setClient( ChatClient client ) 
{ this.client = client; } 
public ClientUI() 
{ 
super("客户端"); 
Container contain = getContentPane(); 
contain.setLayout( new BorderLayout() ); 
mainArea = new JTextArea(); 
JScrollPane mainAreaP = new JScrollPane( mainArea );//为文本区添加滚动条 
JPanel panel = new JPanel(); 
panel.setLayout( new BorderLayout()); 
sendArea = new JTextArea(3, 8); 
JButton sendBtn = new JButton("发送"); 
sendBtn.addActionListener( new ActionListener() 
{ 
public void actionPerformed(ActionEvent ae) 
{ 
client.sendMsg( sendArea.getText() ); 
mainArea.append( "【客户端】"+sendArea.getText() + "\n" ); 
sendArea.setText(""); 
} 
} 
); 
JPanel ipPanel = new JPanel(); 
ipPanel.setLayout( new FlowLayout( FlowLayout.LEFT , 10, 10 ) ); 
ipPanel.add( new JLabel("服务器：") ); 
ipArea = new JTextField( 12 ) ; 
ipArea.setText( "127.0.0.1" ); 
ipPanel.add( ipArea ); 
btnLink = new JButton("连接"); 
ipPanel.add( btnLink ); 
btnLink.addActionListener( new ActionListener() 
{ 
public void actionPerformed(ActionEvent ae) 
{ 
client = new ChatClient( ipArea.getText() , 6666, ClientUI.this );//创建socket对象 
ClientUI.this.setClient( client ); 
} 
} 
); 
panel.add( sendBtn, BorderLayout.EAST ); 
panel.add( sendArea, BorderLayout.CENTER ); 
contain.add( ipPanel, BorderLayout.NORTH ); 
contain.add( mainAreaP, BorderLayout.CENTER ); 
contain.add( panel, BorderLayout.SOUTH ); 
setSize( 500, 300); 
setVisible( true ); 
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
} 
public static void main(String[] args) 
{ 
ClientUI ui = new ClientUI(); 
} 
} 

/** 
通讯类ChatClient负责守候数据到来 
*/ 
class ChatClient extends Thread 
{ 
Socket sc;// 对象sc，用来处理与服务?鞯耐ㄐ? 
BufferedReader in;//声明输入流缓冲区，用于存储服务器发来的信息 
PrintWriter out;//声明打印输出流，用于信息的发送 
ClientUI ui; 

public ChatClient( String ip, int port, ClientUI ui ){//初始化ChatClient类 
this.ui = ui; 
try{ 
sc = new Socket(ip , port); // 创建sc, 用服务器ip和端口作参数 
System.out.println("已顺利联接到服务器。"); 
out = new PrintWriter( sc.getOutputStream(), true ); 
in = new BufferedReader( new InputStreamReader( sc.getInputStream() ) ); 
} 
catch(Exception e) { 
System.out.println( e ); 
} 
start(); 
} 
public void run () { // 用于监听服务器端发送来的信息 
String msg = ""; 
while( true ) 
{ 
try { 
msg = in.readLine();//从缓冲区读入一行字符存于msg 
} catch( SocketException ex ) { System.out.println(ex); break; } 
catch( Exception ex ) { System.out.println(ex); } 
if( msg!=null && msg.trim()!="" ) 
{//若msg信息不为空 
System.out.println(">>" + msg ); 
ui.mainArea.append( msg + "\n" );//把msg信息添加到客户端的文本区域内 
} 
} 
} 
public void sendMsg( String msg ) {// 用于发送信息 
try { 
out.println("【客户端】" + msg ); 
} 
catch(Exception e) { 
System.out.println( e ); 
} 
} 
} 

老兄，把代码格式化行不？代码放到代码片段不是更好？

呵呵,下次 我再贴的时间 注意

import java.io.*; 
public class ServerClass{ 
public static void main(String args[]){ 
int i=0; 
try{ 
ServerSocket ss=new ServerSocket(2345);//为该服务器开设一个端口，该端口供客户机程序来访问。 
System.out.println("服务器启动......"); 
while(true){ 
Socket sock=ss.accept();//sock对象接收客户机的连接请求，程序运行到这里将处于等待状态。 
i++; 
System.out.println("接受连接请求"+i); 
PrintStream out=new PrintStream(sock.getOutputStream());//获得输出流 
out.println("你好"); 
out.close(); 
sock.close(); 
} 
}catch(IOException e){ 
System.out.println(e); 
} 
} 
} 

import java.io.*;   
public class ServerClass{   
public static void main(String args[]){   
int i=0;   
try{   
ServerSocket ss=new ServerSocket(2345);//为该服务器开设一个端口，该端口供客户机程序来访问。   
System.out.println("服务器启动......");   
while(true){   
Socket sock=ss.accept();//sock对象接收客户机的连接请求，程序运行到这里将处于等待状态。   
i++;   
System.out.println("接受连接请求"+i);   
PrintStream out=new PrintStream(sock.getOutputStream());//获得输出流   
out.println("你好2");   
out.close();   
sock.close();   
}   
}catch(IOException e){   
System.out.println(e);   
}   
}   
}