socket 学习三（在Socket上的实时交流）

网络的伟大之一也是信息共享，Server可以主动向所有Client广播消息，同时Client也可以向其它Client发布消息。下面看看如何开发一个可以实时传递消息的程序。

设计原理：服务器端接受客户端的连接请求，同时启动一个线程处理这个连接，线程不停的读取客户端输入，然后把输入加入队列中，等候处理。在线程启动的同时将线程加入队列中，以便在需要的时候定位和取出。import java.io.*;

import java.net.*;
import java.util.*;
import java.lang.*;

public class Server extends ServerSocket{
	
	private static ArrayList User_List = new ArrayList();
	private static ArrayList Threader = new ArrayList();
	private static LinkedList Message_Array = new LinkedList();
	private static int Thread_Counter = 0;
	private static boolean isClear = true;
	protected static final int SERVER_PORT = 10000;
	protected FileOutputStream LOG_FILE = new FileOutputStream("d:/connect.log", true);
	
	public Server() throws FileNotFoundException, IOException{
		super(SERVER_PORT);
		new Broadcast();
		//append connection log
		Calendar now = Calendar.getInstance();
		String str = "[" + now.getTime().toString() + "] Accepted a connection1512";
		byte[] tmp = str.getBytes();
		LOG_FILE.write(tmp);
		try{
			while (true){
				Socket socket = accept();
				new CreateServerThread(socket);
			}
		}finally{
			close();
		}
	}
	
	public static void main(String[] args) throws IOException{
		new Server();
	}
	
	
	//--- Broadcast
	class Broadcast extends Thread{
		
		public Broadcast(){
			start();
		}
		
		public void run(){
			while (true){
				if (!isClear){
					String tmp = (String)Message_Array.getFirst();
					for (int i = 0; i < Threader.size(); i++){
						CreateServerThread client = (CreateServerThread)Threader.get(i);
						client.sendMessage(tmp);
					}
					Message_Array.removeFirst();
					isClear = Message_Array.size() > 0 ? false : true;
				}
			}
		}
	}

	//--- CreateServerThread
	class CreateServerThread extends Thread{
		
		private Socket client;
		private BufferedReader in;
		private PrintWriter out;
		private String Username;
		
		public CreateServerThread(Socket s) throws IOException{
			client = s;
			in = new BufferedReader(new InputStreamReader(client.getInputStream()));
			out = new PrintWriter(client.getOutputStream(), true);
			out.println("--- Welcome to this chatroom ---");
			out.println("Input your nickname:");
			start();
		}
		
		public void sendMessage(String msg){
			out.println(msg);
		}

		public void run(){
			try{
				int flag = 0;
				Thread_Counter++;
				String line = in.readLine();
				while (!line.equals("bye")){
					if (line.equals("l")){
						out.println(listOnlineUsers());
						line = in.readLine();
						continue;
					}
					if (flag++ == 0){
						Username = line;
						User_List.add(Username);
						out.println(listOnlineUsers());
						Threader.add(this);
						pushMessage("[< " + Username + " come on in >]");
					}else{
						pushMessage("<" + Username + ">" + line);
					}
					line = in.readLine();
				}
				out.println("--- See you, bye! ---");
				client.close();
			}catch (IOException e){
				e.printStackTrace();
			}finally{
				try{
					client.close();
				}catch (IOException e){
					e.printStackTrace();
				}
				Thread_Counter--;
				Threader.remove(this);
				User_List.remove(Username);
				pushMessage("[< " + Username + " left>]");
			}
		}
		
		private String listOnlineUsers(){
			String s ="-+- Online list -+-1512";
			for (int i = 0; i < User_List.size(); i++){
				s += "[" + User_List.get(i) + "]1512";
			}
			s += "-+---------------------+-";
			return s;
		}
		
		private void pushMessage(String msg){
			Message_Array.addLast(msg);
			isClear = false;
		}
	}
}