Java通过Socket实现简单多人聊天室

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
 
public class Client{
 
 public static void main(String[] args) throws IOException {
 //创建连接指定Ip和端口的socket
 Socket socket = new Socket("127.0.0.1",5200);
 //获取系统标准输入流
 BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
 PrintWriter out = new PrintWriter(socket.getOutputStream());
 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
 //创建一个线程用于读取服务器的信息
 new Thread(new Runnable() {
  @Override
  public void run() {
  try {
   while (true){
   System.out.println(in.readLine());
   }
  } catch (IOException e) {
   e.printStackTrace();
  }
  }
 }).start();
 //写信息给客户端
 String line = reader.readLine();
 while (!"end".equalsIgnoreCase(line)){
  //将从键盘获取的信息给到服务器
  out.println(line);
  out.flush();
  //显示输入的信息
  line = reader.readLine();
 }
 out.close();
 in.close();
 socket.close();
 
 }
}

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.List;
import java.util.Vector;
 
public class Servers {
 //将接收到的socket变成一个集合
 protected static List<Socket> sockets = new Vector<>();
 
 public static void main(String[] args) throws IOException {
 //创建服务端
 ServerSocket server = new ServerSocket(5200);
 boolean flag = true;
 //接受客户端请求
 while (flag){
  try {
  //阻塞等待客户端的连接
  Socket accept = server.accept();
  synchronized (sockets){
  sockets.add(accept);
  }
  //多个服务器线程进行对客户端的响应
  Thread thread = new Thread(new ServerThead(accept));
  thread.start();
  //捕获异常。
  }catch (Exception e){
  flag = false;
  e.printStackTrace();
  }
 }
 //关闭服务器
 server.close();
 }
 
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
 
/**
 * 服务器线程，主要来处理多个客户端的请求
 */
public class ServerThead extends Servers implements Runnable{
 
 Socket socket;
 String socketName;
 
 public ServerThead(Socket socket){
 this.socket = socket;
 }
 @Override
 public void run() {
 try {
  BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
  //设置该客户端的端点地址
  socketName = socket.getRemoteSocketAddress().toString();
  System.out.println("Client@"+socketName+"已加入聊天");
  print("Client@"+socketName+"已加入聊天");
  boolean flag = true;
  while (flag)
  {
  //阻塞，等待该客户端的输出流
  String line = reader.readLine();
  //若客户端退出，则退出连接。
  if (line == null){
   flag = false;
   continue;
  }
  String msg = "Client@"+socketName+":"+line;
  System.out.println(msg);
  //向在线客户端输出信息
  print(msg);
  }
 
  closeConnect();
 } catch (IOException e) {
  try {
  closeConnect();
  } catch (IOException e1) {
  e1.printStackTrace();
  }
 }
 }
 /**
 * 向所有在线客户端socket转发消息
 * @param msg
 * @throws IOException
 */
 private void print(String msg) throws IOException {
 PrintWriter out = null;
 synchronized (sockets){
 for (Socket sc : sockets){
  out = new PrintWriter(sc.getOutputStream());
  out.println(msg);
  out.flush();
 }
 }
 }
 /**
 * 关闭该socket的连接
 * @throws IOException
 */
 public void closeConnect() throws IOException {
 System.out.println("Client@"+socketName+"已退出聊天");
 print("Client@"+socketName+"已退出聊天");
 //移除没连接上的客户端
 synchronized (sockets){
  sockets.remove(socket);
 }
 socket.close();
 }
}