聊天系统的设计跟普通网站设计有着许多不同的地方，普通网站设计所考虑的因素，例如，普通网站需要对布局进入大量美化以及动画设计等等，而聊天室只要提供满足访客双方直接实时聊天即可。因此，在设计聊天系统的过程中，必须要考虑好以下几个设计要点：
在Internet上的聊天程序一般都是以服务器提供服务端连接响应，使用者通过客户端程序登录到服务器，就可以与登录在同一服务器上的用户交谈，这是一个面向连接的通信过程。因此，程序要在TCP/IP环境下，实现服务器端和客户端两部分程序。
1．首先通过继承JFrame类构造服务器界面。
2．设计客户端程序使其能够完成正常的通信功能
3．设计侦听程序，使其显示登录的ip地址端口号，以及用户昵称，通过侦听按钮可以调用客户端程序，实现聊天功能。
以下为源代码：
（1）ActionProcess.java
package chat;
import java.awt.event.ActionEvent;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.*;
import javax.swing.JOptionPane;
public class ActionProcess implements Runnable {
private ChatClient client;
String name="";
String sendtoname="";
String sendtoID;
String filename="";
String filepath="";
public ActionProcess(ChatClient client) {
this.client=client;
}
public void action(ActionEvent e)throws Exception{
if(e.getSource()==client.connection)
{
try
{
if(client.socket.isConnected()){}
else
{
String addr=JOptionPane.showInputDialog("请输入服务器IP:");
InetAddress address=InetAddress.getByName(addr);
InetSocketAddress socketAddress=new InetSocketAddress(address,5555);
client.socket.connect(socketAddress);
client.in=new DataInputStream(client.socket.getInputStream());
client.out=new DataOutputStream(client.socket.getOutputStream());
name=client.inputName.getText();
client.out.writeUTF("姓名为"+name+"的朋友风尘仆仆地上线了...");
client.listen.setEnabled(true);
client.filesend.setEnabled(true);
client.sendtoall.setEnabled(true);
client.sendtoone.setEnabled(true);
client.emote.setEnabled(true);
if(!(client.thread.isAlive()))
client.thread=new Thread(this);
client.thread.start();
}
}
catch(IOException ee){}
}
if(e.getSource()==client.listen)
{
try
{
name=client.inputName.getText();
client.out.writeUTF("姓名为"+name+"的朋友正在监听中...");
filesendServer filesendserver=new filesendServer();
filesendserver.filereceive();
}
catch (Exception ee) {
ee.printStackTrace();
}
}
if(e.getSource()==client.filesend){
if(client.socket.isConnected())
try {
filesendClient filesendclient=new filesendClient();
filesendclient.filesend();
client.out.writeUTF("成功发送文件！");
}catch (Exception ee){}
}
if(e.getSource()==client.exit)
{
if(client.socket.isConnected())
try {
name=client.inputName.getText();
client.out.writeUTF("姓名为"+name+"的朋友黯然下线了...");
client.out.flush();
client.out.close();
client.socket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
System.exit(0);
}
String em=client.emote.getSelectedItem().toString();
if (em.equals("表情")) {
em = "";
} else {
em += "着";
}
if(e.getSource()==client.sendtoall)
{
if(client.socket.isConnected()){
name=client.inputName.getText();
String s=client.inputContent.getText();
if(s!=null)
{
try
{
client.out.writeUTF(name+em+"对大家说："+s);
client.out.flush();
client.inputContent.setText("");
}
catch(IOException e1){}
}
}
}
if(e.getSource()==client.sendtoone)
{
if(client.socket.isConnected()){
sendtoID=JOptionPane.showInputDialog("请输入对方ID:");
sendtoname=JOptionPane.showInputDialog("请输入对方姓名:");
String s=client.inputContent.getText();
name=client.inputName.getText();
if(s!=null)
{
try
{
client.out.writeUTF(name+" 悄 悄 地 "+em+" 对 <"+sendtoID+">"+sendtoname+"说："+s);
client.out.flush();
client.inputContent.setText("");
}
catch(IOException e1){}
}
}
}
}
public void run()
{
String s=null;
while(true)
{
try
{
s=client.in.readUTF();
client.chatResult.append("\n"+s);
}
catch(IOException e)
{
client.chatResult.setText("与服务器断开连接");
try
{
client.socket.close();
}
catch(Exception ep){}
break;
}
}
}
}
（2）Clicent.java
package chat;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.awt.event.*;
import javax.swing.*;
public class Client {
public static void main(String args[])
{
new ChatClient();
}
}
class ChatClient extends Frame implements ActionListener, Runnable{
private static final long serialVersionUID = -4149839042245330513L;
public Button listen,connection,sendtoall,sendtoone,exit,filesend;
public JComboBox emote;
public TextField inputName,inputContent;
public TextArea chatResult;
public Socket socket=null;
public DataInputStream in=null;
public DataOutputStream out=null;
public Thread thread;
ChatClient()
{
socket=new Socket();
Box box1=Box.createHorizontalBox();
listen=new Button("作为服务器监听");
connection=new Button("连接服务器");
filesend=new Button("发送文件");
exit=new Button("退出");
sendtoall=new Button("群聊");
sendtoone=new Button("私聊");
listen.setEnabled(false);
filesend.setEnabled(false);
sendtoall.setEnabled(false);
sendtoone.setEnabled(false);
inputName=new TextField(6);
inputName.setBackground(new Color(162,231,250));
inputContent=new TextField(22);
inputContent.setBackground(new Color(162,231,250));
chatResult= new TextArea("", 17,20,TextArea.SCROLLBARS_VERTICAL_ONLY);
chatResult.setBackground(new Color(162,231,250));
JLabel jlname=new JLabel("输入昵称");
box1.add(jlname);
box1.add(inputName);
box1.add(listen);
box1.add(connection);
box1.add(filesend);
box1.add(exit);
Box box2=Box.createHorizontalBox();
emote = new JComboBox();
emote.setModel(new DefaultComboBoxModel(new String[] { "表情", "微笑", "甜笑", "惊喜", "嘻嘻", "扮酷", "嘿嘿", "傻笑", "好奇", "媚眼", "鬼脸", "陶醉", "害羞", "生气", "嚷嚷", "发怒", "伤心", "高明", "菜鸟", "问号", "狂笑", "大哭", "示爱", "呻吟", "想想" }));
emote.setEnabled(false);
JLabel jlintput = new JLabel("输入聊天内容");
box2.add(jlintput);
box2.add(inputContent);
box2.add(emote);
box2.add(sendtoall);
box2.add(sendtoone);
listen.addActionListener(this);
connection.addActionListener(this);
filesend.addActionListener(this);
exit.addActionListener(this);
sendtoall.addActionListener(this);
sendtoone.addActionListener(this);
Box box3=Box.createHorizontalBox();
box3.add(chatResult);
thread=new Thread(this);
Box box0=Box.createVerticalBox();
box0.add(Box.createVerticalStrut(10));
box0.add(box1);
box0.add(Box.createVerticalStrut(10));
box0.add(box3);
box0.add(Box.createVerticalStrut(10));
box0.add(box2);
box0.add(Box.createVerticalStrut(10));
add(box0);
setBounds(10,30,500,400);
setBackground(new Color(80,212,248));
setVisible(true);
validate();
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
try {
socket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
});
}
public void actionPerformed(ActionEvent e) {
ActionProcess actionProcess=new ActionProcess(this);
try {
actionProcess.action(e);
} catch (Exception e1) {
e1.printStackTrace();
}
}
public void run()
{
String s=null;
while(true) {
try
{
s=in.readUTF();
chatResult.append("\n"+s);
}
catch(IOException e)
{
chatResult.setText("与服务器断开连接");
try
{
socket.close();
} catch(Exception ep){}
break;
}
}
}
}
（3）ChatServer.java
package chat;
import java.net.*;
import java.io.*;
import java.util.*;
public class ChatServer
{
public static void main(String[] args)throws Exception{
ServerSocket svSocket =null;
Vector threads = new Vector();
try {
svSocket = new ServerSocket(5555);
System.out.println ("listening...");
}catch (Exception ex) {
System.out.println ("Server create ServerSocket failed!");
return;
}
try{
int nid = 0;
while(true){
Socket socket = svSocket.accept();
System.out.println ("accept a client");
ServerThread st = new ServerThread(socket,threads);
st.setID(nid++);
threads.add(st);
new Thread(st).start();
for(int i=0;i < threads.size();i++){
ServerThread temp = (ServerThread)threads.elementAt(i);
}
System.out.println ("Listen again...");
}
}catch(Exception ex){
System.out.println ("server is down");
}
}
}
class ServerThread implements Runnable{
private Vector threads;
private Socket socket = null;
private DataInputStream in = null;
private DataOutputStream out = null;
private int nid;
public ServerThread(Socket socket,Vector threads){
this.socket = socket;
this.threads = threads;
try {
in = new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
}
catch (Exception ex) {
}
}
public void run(){
System.out.println ("Thread is running");
try{
while(true){
String receive = in.readUTF();
if(receive == null)
return;
if(receive.contains("黯然下线了")){
for(int i=0;i < threads.size();i++){
ServerThread st = (ServerThread)threads.elementAt(i);
st.write("***"+receive+"***");
}
}
else if(receive.contains("上线了")){
for(int i=0;i < threads.size();i++){
ServerThread st = (ServerThread)threads.elementAt(i);
st.write("<"+getID()+">: "+receive);
}
}
else if(receive.contains("监听中")){
for(int i=0;i < threads.size();i++){
ServerThread st = (ServerThread)threads.elementAt(i);
st.write("***"+receive+"*** ");
}
}
else if(receive.contains("说")){
if(receive.contains("大家")){
for(int i=0;i < threads.size();i++){
ServerThread st = (ServerThread)threads.elementAt(i);
st.write("<"+getID()+">: "+receive);
}
}
else{
int temp=receive.indexOf("<");
int temp1=receive.indexOf(">");
String tempS=receive.substring(temp+1,temp1);
int i=Integer.parseInt(tempS);
ServerThread st = (ServerThread)threads.elementAt(i);
st.write("<"+getID()+">: "+receive);
st = (ServerThread)threads.elementAt(getID());
st.write("<"+getID()+">: "+receive);
}
}
else{
ServerThread st = (ServerThread)threads.elementAt(getID());
st.write("***"+receive+"***");
}
}
}catch(Exception ex){
threads.removeElement(this);
ex.printStackTrace();
}
try{
socket.close();
}catch(Exception ex){
ex.printStackTrace();
}
}
public void write(String msg){
synchronized(out){
try{
out.writeUTF(msg);
}catch(Exception ex){
}
}
}
public int getID(){
return this.nid;
}
public void setID(int nid){
this.nid = nid;
}
}
（4）fliesendClient.java
package chat;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import javax.swing.JOptionPane;
public class filesendClient {
public void filesend() throws Exception{
String sendtoIP=JOptionPane.showInputDialog("请输入对方IP:");
Socket socket = new Socket(sendtoIP, 1234);
BufferedReader br = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
PrintStream ps = new PrintStream(socket.getOutputStream());
File file = getFile();
ps.println(file.getName());
ps.println(file.length());
String msg = br.readLine();
if("已存在".equals(msg)){
JOptionPane.showMessageDialog(null,"文件已存在,请不要重复上传!");
return;
}
long finishLen = Long.parseLong(msg);
FileInputStream fis = new FileInputStream(file);
OutputStream out = socket.getOutputStream();
byte[] buffer = new byte[1024];
int len;
fis.skip(finishLen);
while((len = fis.read(buffer)) != -1)
out.write(buffer, 0, len);
fis.close();
socket.close();
}
public File getFile() throws Exception{
File file=null;
boolean flag=false;
while(flag==false){
String filepath=JOptionPane.showInputDialog("请输入要上传的路径:");
file = new File(filepath);
if(!file.exists()){
JOptionPane.showMessageDialog(null,"您输入的路径不存在,请重新输入！");
flag=false;
}
else if(file.isDirectory()){
JOptionPane.showMessageDialog(null,"占不支持文件夹上传!请输入一个 文件路径！");
flag=false;
}
else flag=true;
}
return file;
}
}
（5）filesendServer.java
package chat;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JOptionPane;
public class filesendServer{
public void filereceive() throws Exception{
ServerSocket serverSocket = new ServerSocket(1234);
JOptionPane.showMessageDialog(null,"服务已启动,绑定1234端口!");
while(true){
Socket socket = serverSocket.accept();
new fileServerThread(socket).start();
}
}
}
class fileServerThread extends Thread{
Socket socket;
public fileServerThread(Socket socket) {
this.socket = socket;
}
public void run() {
FileOutputStream fos = null;
try {
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintStream ps = new PrintStream(socket.getOutputStream());
String fileName = br.readLine();
long fileLen = Long.parseLong(br.readLine());
File dir = new File("upload");
dir.mkdir();
File file = new File(dir,fileName);
if(file.exists() && file.length() == fileLen){
ps.println("已存在");
return;
}
else{
ps.println(file.length());
}
String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
System.out.println(time + " "+ (file.exists() ? " 开始断点续传: " : " 开始上传文件: ") + file.getName());
long start = System.currentTimeMillis();
InputStream in = socket.getInputStream();
fos = new FileOutputStream(file, true);
byte[] buffer = new byte[1024];
int len;
while((len = in.read(buffer)) != -1){
fos.write(buffer, 0, len);
if(file.length() == fileLen)
break;
}
fos.close();
long end = System.currentTimeMillis();
time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
System.out.println(time + " " + " 上传文件结束: " + file.getName() + ", 耗时: " + (end - start) + "毫秒");
ps.println("上传成功");
socket.close();
} catch (IOException e) {
if(fos != null)
try {
fos.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}