Java/Network Protocol/DatagramSocket
Содержание
- 1 Datagram Sender
- 2 DatagramSocket receives DatagramPacket
- 3 DatagramSocket sends out DatagramPacket
- 4 Joining a Multicast Group
- 5 Read and write with DatagramPacket
- 6 Receive DatagramPacket
- 7 Receiving a Datagram
- 8 Receiving from a Multicast Group
- 9 Send a Datagram
- 10 Send back the response in a DatagramPacket
- 11 Sending a Datagram
- 12 Sending to a Multicast Group
- 13 Use DatagramSocket to send out and receive DatagramPacket
- 14 User Datagram Protocol Programming
Datagram Sender
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; class DatagramSender {
public static void main(String args[]) throws Exception {
InetAddress ia = InetAddress.getByName(args[0]);
// Obtain destination port
int port = Integer.parseInt(args[1]);
// Create a datagram socket
DatagramSocket ds = new DatagramSocket();
// Create a datagram packet
byte buffer[] = args[2].getBytes();
DatagramPacket dp = new DatagramPacket(buffer, buffer.length, ia, port);
ds.send(dp);
}
}
</source>
DatagramSocket receives DatagramPacket
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; public class Main {
public static void main(String[] args) throws Exception {
DatagramSocket ds = new DatagramSocket(3000);
byte[] buf = new byte[1024];
DatagramPacket dp = new DatagramPacket(buf, 1024);
ds.receive(dp);
String strRecv = new String(dp.getData(), 0, dp.getLength()) + " from "
+ dp.getAddress().getHostAddress() + ":" + dp.getPort();
System.out.println(strRecv);
ds.close();
}
}
</source>
DatagramSocket sends out DatagramPacket
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main {
public static void main(String[] args) throws Exception {
DatagramSocket ds = new DatagramSocket();
String str = "hello world";
InetAddress ia = InetAddress.getByName("127.0.0.1");
DatagramPacket dp = new DatagramPacket(str.getBytes(), str.length(), ia, 3000);
ds.send(dp);
ds.close();
}
}
</source>
Joining a Multicast Group
<source lang="java">
import java.net.InetAddress; import java.net.MulticastSocket; public class Main {
public static void main(String[] argv) throws Exception {
String groupName = "groupName";
int port = 1024;
MulticastSocket msocket = new MulticastSocket(port);
InetAddress group = InetAddress.getByName(groupName);
msocket.joinGroup(group);
}
}
</source>
Read and write with DatagramPacket
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main {
public static void main(String[] args) throws Exception {
byte[] ary = new byte[128];
DatagramPacket pack = new DatagramPacket(ary, 128);
// read
DatagramSocket sock = new DatagramSocket(1111);
sock.receive(pack);
String word = new String(pack.getData());
System.out.println("From: " + pack.getAddress() + " Port: " + pack.getPort());
System.out.println(word);
sock.close();
// write
sock = new DatagramSocket();
pack.setAddress(InetAddress.getByName(args[1]));
pack.setData(args[2].getBytes());
pack.setPort(1111);
sock.send(pack);
sock.close();
}
}
</source>
Receive DatagramPacket
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; class Collector {
private final static int BUFSIZE = 20;
public static void main(String args[]) throws Exception {
int port = Integer.parseInt(args[0]);
DatagramSocket ds = new DatagramSocket(port);
while (true) {
byte buffer[] = new byte[BUFSIZE];
DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
ds.receive(dp);
System.out.println(new String(dp.getData()));
}
}
}
</source>
Receiving a Datagram
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; public class Main {
public static void main(String[] argv) throws Exception {
byte[] inbuf = new byte[256]; // default size
DatagramSocket socket = new DatagramSocket();
DatagramPacket packet = new DatagramPacket(inbuf, inbuf.length);
socket.receive(packet);
int numBytesReceived = packet.getLength();
System.out.println(numBytesReceived);
}
}
</source>
Receiving from a Multicast Group
<source lang="java">
import java.net.DatagramPacket; import java.net.MulticastSocket; public class Main {
public static void main(String[] argv) throws Exception {
MulticastSocket msocket = new MulticastSocket(9999);
byte[] inbuf = new byte[1024];
DatagramPacket packet = new DatagramPacket(inbuf, inbuf.length);
msocket.receive(packet);
// Data is now in inbuf
int numBytesReceived = packet.getLength();
}
}
</source>
Send a Datagram
<source lang="java">
import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; public class Main {
public static void main(String[] argv) throws Exception {
}
public static void senddatagram(InetAddress target, int port, byte[] outbuf, int len) {
try {
DatagramPacket request = new DatagramPacket(outbuf, len, target, port);
DatagramSocket socket = new DatagramSocket();
socket.send(request);
} catch (SocketException e) {
} catch (IOException e) {
}
}
}
</source>
Send back the response in a DatagramPacket
<source lang="java">
import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.util.Date; public class Main {
final private static int DAYTIME_PORT = 13;
public static void main(String args[]) throws IOException {
DatagramSocket socket = new DatagramSocket(DAYTIME_PORT);
while (true) {
byte buffer[] = new byte[256];
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
socket.receive(packet);
String date = new Date().toString();
buffer = date.getBytes();
// Get response address/port for client from packet
InetAddress address = packet.getAddress();
int port = packet.getPort();
packet = new DatagramPacket(buffer, buffer.length, address, port);
socket.send(packet);
}
}
}
</source>
Sending a Datagram
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main {
public static void main(String[] argv) throws Exception {
InetAddress dst = InetAddress.getLocalHost();
int port = 8080;
byte[] outbuf = new byte[1024];
int len = 1024;
DatagramPacket request = new DatagramPacket(outbuf, len, dst, port);
DatagramSocket socket = new DatagramSocket();
socket.send(request);
}
}
</source>
Sending to a Multicast Group
<source lang="java">
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main {
public static void main(String[] argv) throws Exception {
byte[] outbuf = new byte[1024];
int port = 1234;
DatagramSocket socket = new DatagramSocket();
InetAddress groupAddr = InetAddress.getByName("8.1.2.3");
DatagramPacket packet = new DatagramPacket(outbuf, outbuf.length, groupAddr, port);
socket.send(packet);
}
}
</source>
Use DatagramSocket to send out and receive DatagramPacket
<source lang="java">
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class ChatClient {
public static void main(String[] args) throws Exception {
DatagramSocket s = new DatagramSocket();
byte[] buf = new byte[1000];
DatagramPacket dp = new DatagramPacket(buf, buf.length);
InetAddress hostAddress = InetAddress.getByName("localhost");
while (true) {
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
String outMessage = stdin.readLine();
if (outMessage.equals("bye"))
break;
String outString = "Client say: " + outMessage;
buf = outString.getBytes();
DatagramPacket out = new DatagramPacket(buf, buf.length, hostAddress, 9999);
s.send(out);
s.receive(dp);
String rcvd = "rcvd from " + dp.getAddress() + ", " + dp.getPort() + ": "
+ new String(dp.getData(), 0, dp.getLength());
System.out.println(rcvd);
}
}
}
import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.DatagramPacket; import java.net.DatagramSocket; public class ChatServer {
public static void main(String[] args) throws Exception {
int PORT = 4000;
byte[] buf = new byte[1000];
DatagramPacket dgp = new DatagramPacket(buf, buf.length);
DatagramSocket sk;
sk = new DatagramSocket(PORT);
System.out.println("Server started");
while (true) {
sk.receive(dgp);
String rcvd = new String(dgp.getData(), 0, dgp.getLength()) + ", from address: "
+ dgp.getAddress() + ", port: " + dgp.getPort();
System.out.println(rcvd);
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
String outMessage = stdin.readLine();
buf = ("Server say: " + outMessage).getBytes();
DatagramPacket out = new DatagramPacket(buf, buf.length, dgp.getAddress(), dgp.getPort());
sk.send(out);
}
}
}
</source>
User Datagram Protocol Programming
<source lang="java">
import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main {
final private static int DAYTIME_PORT = 13;
public static void main(String args[]) throws IOException {
String host = args[0];
byte message[] = new byte[256];
InetAddress address = InetAddress.getByName(host);
System.out.println("Checking at: " + address);
DatagramPacket packet = new DatagramPacket(message, message.length, address, DAYTIME_PORT);
DatagramSocket socket = new DatagramSocket();
socket.send(packet);
packet = new DatagramPacket(message, message.length);
socket.receive(packet);
String time = new String(packet.getData());
System.out.println(time);
socket.close();
}
}
</source>
