昨天回忆了一下以前做的一个实时的群聊小程序。用JAVA写得。开发步骤如下：
这是面向过程的开发。
第一步，建立服务器端。
第二步，建立客户端并连接服务端。
第三步，客户端发送消息服务器端能接收到。
第四步，实现多客户连接服务端，并能接收多客户端发来的消息。可以采用多线程和异步的方法解决服务端被占用的情况。
第五步，服务端转发客户端发送的信息到每一个客户端。
第六步，消除小Bug。
ChatServer.java
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.util.*;
import java.io.IOException;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
public class ChatServer
{
boolean started = false;
ServerSocket ss = null;
List clients = new ArrayList();
public static void main(String[] args)
{
new ChatServer().start();
}
public void start(){
try
{
ss = new ServerSocket(8881);
}
catch (BindException e){
System.out.println("端口已被占用！");
System.out.println("请结束相关进程！");
System.exit(0);
}
catch (Exception e) {
e.printStackTrace();
}
try{
started = true;
while (started)
{
Socket s = ss.accept(); //阻塞性函数，不断接收客户端连接
Client c = new Client(s);//不能再静态main()里面new一个动态的方法,故将启动过程包装成一个public函数
System.out.println("a client connected");
new Thread(c).start();
clients.add(c);
}
}
catch (Exception e)
{
e.printStackTrace();
}finally{
try
{
ss.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class Client implements Runnable{//区分客户端，用一个线程操作一个客户端，也可以采用异步的方法。这里用线程，比较占资源。等我写出异步的方法后再共享。
private Socket s= null;
private DataInputStream dis= null;
private DataOutputStream dos=null;
private boolean bConnected = false;
public Client(Socket s){
this.s= s;
try
{
dis=new DataInputStream(s.getInputStream());
dos=new DataOutputStream(s.getOutputStream());
bConnected = true;
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void send(String str){ //
try
{
dos.writeUTF(str);
} catch (IOException e)
{
// TODO Auto-generated catch block
clients.remove(this);
System.out.println("一个客户退出了！List已去除");
//e.printStackTrace();
}
}
public void run()
{
try
{
while (bConnected)
{
String str;
str = dis.readUTF();// 阻塞性函数，会一直占用线程资源
System.out.println(str);
for (int i = 0; i < clients.size(); i++)
{
Client c = clients.get(i);
c.send(str);
}
}
}
catch (EOFException e){
System.out.println("一个客户已退出！");
}catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(dis!=null)
try
{
dis.close();
if (dos != null)
dos.close();
if (s != null)
s.close();
} catch (SocketException e)
{
clients.remove(this);
System.out.println("一个客户已退出！");
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
ChatClient.java
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.Socket;
import java.net.SocketException;
import java.net.UnknownHostException;
public class ChatClient extends Frame
{
Socket s = null;
DataOutputStream dos = null;
DataInputStream dis = null;
private boolean bConnected=false;
TextField tfTxt = new TextField();//输入框
TextArea taContent = new TextArea();//显示聊天信息框
public static void main(String[] args)
{
new ChatClient().lanunchFrame();
}
public void lanunchFrame(){
setLocation(400,300);
this.setSize(300, 300);
add(tfTxt,BorderLayout.SOUTH);
add(taContent,BorderLayout.NORTH);
pack();//调整空隙
this.addWindowListener(new WindowAdapter(){
@Override
public void windowClosing(WindowEvent e)
{
disconnect();
System.exit(0);
}
});
tfTxt.addActionListener(new TexFileListener());
setVisible(true);
connect();
new Thread(new RecvThread()).start();
}
public void connect(){
try
{
s= new Socket("127.0.0.1",8881);
dos=new DataOutputStream(s.getOutputStream());
dis=new DataInputStream(s.getInputStream());
System.out.println("connected!");
bConnected =true;
} catch (UnknownHostException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
}
public void disconnect()
{
try
{
dos.close();
dis.close();
s.close();
} catch (Exception e1)
{
e1.printStackTrace();
}
/*try
{
bConnected = false; //保证
recvThread.join();
}
catch (InterruptedException e){
e.printStackTrace();
}
finally{
try
{
dos.close();
dis.close();
s.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
*/
}
private class TexFileListener implements ActionListener{
public void actionPerformed(ActionEvent e)
{
String str=tfTxt.getText().trim();
//taContent.setText(str);
tfTxt.setText("");
try
{
dos.writeUTF(str);
dos.flush();
//dos.close();
} catch (IOException e1)
{
e1.printStackTrace();
}
}
}
private class RecvThread implements Runnable{
public void run()
{
try
{
while (bConnected)
{
String str = dis.readUTF();
//System.out.println(str);
taContent.setText(taContent.getText()+str+'\n');
}
}
catch (SocketException e){
System.out.println("已退出！");
}
catch (EOFException e){
System.out.println("已退出！");
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}