import java.io.*;
import java.net.*;class UDPClient { public static void main(String args[]) throws Exception { DatagramSocket clientSocket = new DatagramSocket();
String serverHostname = new String("127.0.0.1"); InetAddress IPAddress = InetAddress.getByName(serverHostname);
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
System.in));
String sentence;
int a ;
byte[] receiveData = new byte[5120];
while((sentence = inFromUser.readLine())!=null) {
byte[] sendData = new byte[5120];
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, IPAddress, 20001);
clientSocket.send(sendPacket);
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
clientSocket.setSoTimeout(3000);
?????????????????????????????????????
clientSocket.receive(receivePacket);
String modifiedSentence = new String(receivePacket.getData()); InetAddress returnIPAddress = receivePacket.getAddress();
System.out.println("From: " + returnIPAddress);
System.out.println("Message: " + modifiedSentence);
clientSocket.close();
}
}
import java.io.*;
import java.net.*;class UDPServer {
public static void main(String args[]) throws Exception {
// Create a Server Datagram Socket binded to Port 20001
DatagramSocket serverSocket = new DatagramSocket(20001); // The Datagram is 5K
byte[] receiveData = new byte[5120];
byte[] sendData = new byte[5120]; // Counter
int i = 1;
while (true) {
// Receive a Packet if i = odd number
if (i % 2 != 0) {
receiveData = new byte[5120];
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
serverSocket.receive(receivePacket);
i++;
String sentence = new String(receivePacket.getData());
InetAddress IPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
System.out.println("From: " + IPAddress + ":" + port);
System.out.println("Message: " + sentence);
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, IPAddress, port);
serverSocket.send(sendPacket);
}
}
}
}
当server收到消息 会发个ACK给client 如果client 过了3秒钟没收到 重发之前的消息 我在server里准备每第2个收不到 来test 谁会帮帮写下client没收到 重发消息吗 在serverclass里面 谢谢 急!!!!小弟新手 麻烦写相信点
import java.net.*;class UDPClient { public static void main(String args[]) throws Exception { DatagramSocket clientSocket = new DatagramSocket();
String serverHostname = new String("127.0.0.1"); InetAddress IPAddress = InetAddress.getByName(serverHostname);
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
System.in));
String sentence;
int a ;
byte[] receiveData = new byte[5120];
while((sentence = inFromUser.readLine())!=null) {
byte[] sendData = new byte[5120];
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, IPAddress, 20001);
clientSocket.send(sendPacket);
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
clientSocket.setSoTimeout(3000);
?????????????????????????????????????
clientSocket.receive(receivePacket);
String modifiedSentence = new String(receivePacket.getData()); InetAddress returnIPAddress = receivePacket.getAddress();
System.out.println("From: " + returnIPAddress);
System.out.println("Message: " + modifiedSentence);
clientSocket.close();
}
}
import java.io.*;
import java.net.*;class UDPServer {
public static void main(String args[]) throws Exception {
// Create a Server Datagram Socket binded to Port 20001
DatagramSocket serverSocket = new DatagramSocket(20001); // The Datagram is 5K
byte[] receiveData = new byte[5120];
byte[] sendData = new byte[5120]; // Counter
int i = 1;
while (true) {
// Receive a Packet if i = odd number
if (i % 2 != 0) {
receiveData = new byte[5120];
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
serverSocket.receive(receivePacket);
i++;
String sentence = new String(receivePacket.getData());
InetAddress IPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
System.out.println("From: " + IPAddress + ":" + port);
System.out.println("Message: " + sentence);
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, IPAddress, port);
serverSocket.send(sendPacket);
}
}
}
}
当server收到消息 会发个ACK给client 如果client 过了3秒钟没收到 重发之前的消息 我在server里准备每第2个收不到 来test 谁会帮帮写下client没收到 重发消息吗 在serverclass里面 谢谢 急!!!!小弟新手 麻烦写相信点
这个应该到处都有类似的程序,比如THINK IN JAVA里面就有源代码的。另外UDP是无序的, 所以你需要制定包格式,来识别是哪个消息,是第几次送的等等。
就把源代码放到了地址:http://download.csdn.net/source/1184505