[英]How to group 2 udp clients?
我正在嘗試做的是第 2 組客戶並使他們相互交流。 因此,如果連接了 2 個客戶端,它們將只能相互通信,如果連接了第三個客戶端,它將無法與其他 2 個客戶端進行通信,但它會創建另一組 2 個客戶端,依此類推......對現在,如果客戶端發送一條消息,它會將其發送給所有客戶端,但我不知道如何使其按上述方式工作。 通過在控制台中鍵入一些內容從客戶端發送消息。
服務器:
public class Server extends Thread{
public final static int PORT = 7331;
private final static int BUFFER = 1024;
private DatagramSocket socket;
private ArrayList<InetAddress> clientAddresses;
private ArrayList<Integer> clientPorts;
private HashSet<String> existingClients;
public Server() throws IOException {
socket = new DatagramSocket(PORT);
System.out.println("[SERVER] UDP server successfully launched on port " + PORT);
clientAddresses = new ArrayList<InetAddress>();
clientPorts = new ArrayList<Integer>();
existingClients = new HashSet<String>();
}
public void run() {
byte[] buf = new byte[BUFFER];
while (true) {
try {
//resets buffer so only new messages get displayed
Arrays.fill(buf, (byte) 0);
DatagramPacket packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);
String content = new String(buf, buf.length);
InetAddress clientAddress = packet.getAddress();
int clientPort = packet.getPort();
String id = clientAddress.toString() + "," + clientPort;
if (!existingClients.contains(id)) {
existingClients.add(id);
clientPorts.add(clientPort);
clientAddresses.add(clientAddress);
}
System.out.println(id + " : " + content);
byte[] data = (id + " : " + content).getBytes();
for (int i = 0; i < clientAddresses.size(); i++) {
InetAddress cl = clientAddresses.get(i);
int cp = clientPorts.get(i);
packet = new DatagramPacket(data, data.length, cl, cp);
socket.send(packet);
}
} catch (Exception e) {
System.err.println(e);
}
}
}
public static void main(String args[]) throws Exception {
Server s = new Server();
s.start();
}
}
客戶:
public class Client implements Runnable {
public static void main(String args[]) throws Exception {
String host = "127.0.0.1";
DatagramSocket socket = new DatagramSocket();
//handles the receiving part for every client (incoming packets to clients)
MessageReceiver r = new MessageReceiver(socket);
Client s = new Client(socket, host);
Thread rt = new Thread(r);
Thread st = new Thread(s);
rt.start();
st.start();
}
public final static int PORT = 7331;
private DatagramSocket sock;
private String hostname;
Client(DatagramSocket s, String h) {
sock = s;
hostname = h;
}
//sending clients socket to server
private void sendMessage(String s) throws Exception {
//getting bytes from message
byte buf[] = s.getBytes();
//getting hostname from server
InetAddress address = InetAddress.getByName(hostname);
//setting up packet
DatagramPacket packet = new DatagramPacket(buf, buf.length, address, PORT);
//sending packet to server
sock.send(packet);
}
public void run() {
//connected boolean is used to send a greetings message once for every new client that has joined
boolean connected = false;
do {
try {
sendMessage("GREETINGS");
connected = true;
} catch (Exception e) {
}
} while (!connected);
//reads from the console
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
while (true) {
try {
while (!in.ready()) {
Thread.sleep(100);
}
//sends message from console to server
sendMessage(in.readLine());
} catch (Exception e) {
System.err.println(e);
}
}
}
}
//this class handles receiving part of clients
class MessageReceiver implements Runnable {
DatagramSocket sock;
byte buf[];
MessageReceiver(DatagramSocket s) {
sock = s;
buf = new byte[1024];
}
public void run() {
while (true) {
try {
DatagramPacket packet = new DatagramPacket(buf, buf.length);
sock.receive(packet);
String received = new String(packet.getData(), 0,
packet.getLength());
System.out.println(received);
} catch (Exception e) {
System.err.println(e);
}
}
}
}
您正在嘗試的是消息廣播或消息轉發器客戶端。 廣播是在網絡層實現的(使用廣播本地網絡廣播地址)。
如果您以這種方式實施它,當您有 2 個以上的客戶端時,您的網絡就會泛濫。 向您的網絡管理員致以最誠摯的問候。 ;-)
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