三步學會Java Socket編程(三) – JAVA編程語言程序開發技術文章

第三步 實現信息共享:在Socket上的實時交流
網絡的偉大之一也是信息共享,Server可以主動向所有Client廣播消息,同時Client也可以向其它Client發佈消息。下面看看如何開發一個可以實時傳遞消息的程序。
設計原理:
服務器端接受客戶端的連接請求,同時啟動一個線程處理這個連接,線程不停的讀取客戶端輸入,然後把輸入加入隊列中,等候處理。在線程啟動的同時將線程加入隊列中,以便在需要的時候定位和取出。
源碼}
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)
{}
finally
{
try
{
client.close();
}
catch (IOException e)
{}
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;
}
}
}
這就是程序運行後,多用戶登陸並且輸入信息後的屏幕。實現瞭信息的實時廣播。用戶輸入"l"就可以列出在線人員表。

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