Java实现多人聊天室的原理与源码

public class CloseUtil {
 public static void CloseAll(Closeable... closeable){
  for(Closeable c:closeable){
   if (c != null) {
    try {
     c.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
  }
 }
}

//服务器
public class Server {
 //存储每一个连接进来的客户端
 public static List<MyChannel> list=new ArrayList<>();

 public static void main(String[] args) throws Exception {
   //创建ServerSocket对象
  ServerSocket serverSocket = new ServerSocket(9999);
  while (true){
   //连接进来的客户端
   Socket client = serverSocket.accept();
   System.out.println(client.getInetAddress()+"进入聊天室");
  MyChannel myChannel = new MyChannel(client);
  list.add(myChannel);
  new Thread(myChannel).start();
  }
 }
}

//用于信息转发
public class MyChannel implements Runnable{
 private DataInputStream dis;
 private DataOutputStream dos;
 private boolean flag=true;

 public MyChannel(Socket socket) {
  try{
   dis=new DataInputStream(socket.getInputStream());
   dos=new DataOutputStream(socket.getOutputStream());
  }catch (IOException e){
   flag=false;
   CloseUtil.CloseAll(dis,dos);
  }
 }
 //接收数据的方法
 private String receive(){
  String str="";
  try{
   str= dis.readUTF();
  }catch (IOException e){
   flag=false;
   CloseUtil.CloseAll(dis,dos);
   Server.list.remove(this);
  }
  return str;
 }
 //发送数据的方法
 private void send(String str){
  try {
   if (str != null && str.length() != 0) {
    dos.writeUTF(str);
    dos.flush();
   }
  }catch (Exception exception){
   flag=false;
   CloseUtil.CloseAll(dos,dis);
   Server.list.remove(this);
  }
 }
 //转发消息的方法
 private void sendToOther(){
  String str=this.receive();
  List<MyChannel> list = Server.list;
  for (MyChannel other:list) {
   if(other==list){
    continue;//不发送信息给自己
   }
   //将消息发送给其他客户端
   other.send(str);
  }
 }

 @Override
 public void run() {
  while (flag){
   sendToOther();
  }
 }
}

public class Send implements Runnable{
 //从键盘上获取数据
 private BufferedReader br;
 private DataOutputStream dos;
 private boolean flag=true;

 public Send() {
  br=new BufferedReader(new InputStreamReader(System.in));
 }
 public Send(Socket socket){
  this();
  try{
   dos=new DataOutputStream(socket.getOutputStream());
  }catch (Exception e){
   flag=false;
   CloseUtil.CloseAll(dos,socket);
   e.printStackTrace();
  }
 }


 private String getMessage(){
  String str="";
  try{
   str=br.readLine();
  }catch (IOException e){
   flag=false;
   CloseUtil.CloseAll(br);
  }
  return str;
 }
 private void send(String str){
  try {
   dos.writeUTF(str);
   dos.flush();
  } catch (IOException e) {
   flag=false;
   CloseUtil.CloseAll(dos);
   e.printStackTrace();
  }

 }

 @Override
 public void run() {
  while (flag){
   this.send(getMessage());
  }
 }
}

public class Receive implements Runnable{
  //接受数据流
  private DataInputStream dis;
  private boolean flag=true;


  public Receive(Socket socket){
    try {
      dis = new DataInputStream(socket.getInputStream());
    }catch (Exception e){
      flag=false;
      CloseUtil.CloseAll(dis,socket);
    }
  }
  private String getMessage(){
    String str="";
    try {
      str=dis.readUTF();
    } catch (IOException e) {
      flag=false;
      CloseUtil.CloseAll(dis);
      e.printStackTrace();
    }
    return str;
  }
  @Override
  public void run() {
    while (flag){
      System.out.println(this.getMessage());
    }
  }
}

public class client {
  public static void main(String[] args) throws Exception{
    Socket socket = new Socket(InetAddress.getLocalHost(),9999);
    Send send = new Send(socket);
    Receive receive = new Receive(socket);
    new Thread(send).start();
    new Thread(receive).start();
  }
}