以下是一个简单的示例代码,演示了如何在Android平台上使用UDP打洞。
import java.io.IOException;
import java.net.*;
public class UdpHolePunching {
public static void main(String[] args) throws IOException {
// 创建两个UDP套接字
DatagramSocket clientSocket1 = new DatagramSocket();
DatagramSocket clientSocket2 = new DatagramSocket();
// 获取本地IP地址和端口号
InetAddress localAddress = InetAddress.getLocalHost();
int port1 = clientSocket1.getLocalPort();
int port2 = clientSocket2.getLocalPort();
// 创建两个线程分别用于发送和接收UDP数据包
Thread senderThread = new Thread(() -> {
try {
// 向服务器发送包含本地IP地址和端口号的数据包
byte[] sendData = (localAddress.getHostAddress() + ":" + port1).getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, InetAddress.getByName("server-ip"), 12345);
clientSocket1.send(sendPacket);
System.out.println("Sent packet to server: " + new String(sendData));
} catch (IOException e) {
e.printStackTrace();
}
});
Thread receiverThread = new Thread(() -> {
try {
byte[] receiveData = new byte[1024];
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
// 接收服务器发送的数据包,其中包含了另一方的IP地址和端口号
clientSocket2.receive(receivePacket);
String receivedInfo = new String(receivePacket.getData(), 0, receivePacket.getLength());
System.out.println("Received packet from server: " + receivedInfo);
// 解析IP地址和端口号
String[] info = receivedInfo.split(":");
InetAddress remoteAddress = InetAddress.getByName(info[0]);
int remotePort = Integer.parseInt(info[1]);
// 向另一方发送数据包
byte[] sendData = "Hello from client 2".getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, remoteAddress, remotePort);
clientSocket2.send(sendPacket);
System.out.println("Sent packet to client 1: " + new String(sendData));
} catch (IOException e) {
e.printStackTrace();
}
});
// 启动发送和接收线程
senderThread.start();
receiverThread.start();
}
}
请注意,此代码只是一个简单示例,仅用于演示UDP打洞的基本概念。在实际应用中,可能需要更复杂的逻辑来处理网络连接和数据传输。