Java Socket（四）使用UDP傳輸數據

參考資料： UDP Socket 編程

package socket;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDPSocketClient 
{
	public static void main(String[] args) throws IOException 
	{
		//1.定義服務器的地址、端口、數據
		InetAddress address= InetAddress.getByName("localhost");
		int port = 8800;
		byte[] data = "Hello".getBytes();		
		//2建立數據報
		DatagramPacket packet = new DatagramPacket(data, data.length, address, port);	    
		//3建立DatagramSocket
		DatagramSocket socket = new DatagramSocket();
		//4發送數據
	        socket.send(packet);
		System.out.println("Sended");		
		
		
		/*
		 * 接收服務器端相應的信息
		 */
		//1.建立數據報
		byte[] respdata = new byte[1024];
		DatagramPacket resppacket = new DatagramPacket(respdata, respdata.length);
		//2.接收服務器響應的數據
		socket.receive(resppacket);
		//3.轉爲字符串
		String reply = new String(respdata, 0, resppacket.getLength());
		System.out.println("received:" + reply);		
		
		
		//關閉資源
		socket.close();
	}
}


package socket;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDPSocketServer 
{
	public static void main(String[] args) throws IOException 
	{
		// 1建立服務器端，並指定端口
		DatagramSocket socket = new DatagramSocket(8800);
		// 2建立數據報
		byte[] data = new byte[1024];
		DatagramPacket packet = new DatagramPacket(data, data.length);
		// 3 接收客戶端發送的數據
		System.out.println("wait for client...");
		socket.receive(packet);// 此方法在接收到數據以前會一直阻塞
		String info = new String(data, 0, packet.getLength());
		System.out.println("Server side get:" + info);
		
		/*
		 * 向客戶端相應
		 */
		//客戶端地址、端口、數據
		InetAddress address = packet.getAddress();
	        int port = packet.getPort();
	        byte[] respdata = "Hello,too!".getBytes();
	        //建立數據報，並綁定相應信息
	        DatagramPacket resppacket= new DatagramPacket(respdata, respdata.length,
	    		address, port);
	        socket.send(resppacket);	    
	}
}