UDP网络编程

 

UDP是基于无连接的,不可靠的传输   与TCP/IP相反

 

 

 

UDP实现私聊,发送方式客户端,接受方式服务器

package netUDP_sc;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;

/**
 * 发送方
 * 
 * @author Administrator
 * 
 */

public class Sender_V1 {

	public static void main(String[] args) {
		try {
			// 创建发送本地数据对象
			SocketAddress senders = new InetSocketAddress("127.0.0.1", 9090);

			// 创建接受数据对象
			SocketAddress Receiver = new InetSocketAddress("127.0.0.1", 9091);

			// 创建发送方
			DatagramSocket socket = new DatagramSocket(senders);

			int i = 0;
			while (true) {
				// 发送字符串
				byte[] buf = (i + "hello").getBytes();
				// 创建要发送包的对象
				DatagramPacket datapacket = new DatagramPacket(buf, buf.length,
						Receiver);

				socket.send(datapacket);
				i++;

				Thread.sleep(1000);
			}

		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

 

 

接受方;

package netUDP_sc;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

import java.net.InetSocketAddress;
import java.net.SocketAddress;

/**
 * 接受方
 * 
 * @author Administrator
 * 
 */

public class Receiver_V1 {

	public static void main(String[] args) {
		try {
			// 创建接受方
			SocketAddress Receiver = new InetSocketAddress("127.0.0.1", 9091);

			// 创建传递方
			DatagramSocket socket = new DatagramSocket(Receiver);
			// 创建数据缓冲区
			byte[] buf = new byte[20];

			DatagramPacket packet = new DatagramPacket(buf, buf.length);

			while (true) {
				System.out.println("等待接受数据......");
				// 接受数据到包中,如果没有数据则会阻塞
				socket.receive(packet);
				// 获取包中的字节
				byte[] bs = packet.getData();

				// 将字节转化成字符串
				String str = new String(bs);
				// 输出 发送者的ip地址和字符串
				System.out.println(packet.getSocketAddress() + " 发来的" + str);
			}

		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
}

 

 

运行;

等待接受数据......

/127.0.0.1:9090 发来的0hello

..............

 

 

 

 

 

 

UDP实现组播

     2.UDP组播消息

0.0.0.0  255.255.255.255

 

A类地址  1.0.0.0~126.0.0.0

B类地址128.0.0.0~191.254.0.0

C类地址：192.0.0.0~223.255.255.0

D类地址224.0.0.0~239.255.255.254(组播地址)

 

利用MulticastSocket类来实现

  

package netUDP_组播;
/**
 * 发送方
 */
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;

import javax.swing.plaf.multi.MultiButtonUI;

public class SendAll {

	public static void main(String[] args) {
		
		try {
			
			//创建ip
			InetAddress inetAdd = InetAddress.getByName("230.0.0.1");
			int  i = 0 ;
			while(true){
			//创建发送数据包
			byte[] buf =(i+"王佳").getBytes();
			DatagramPacket packet = new DatagramPacket(buf, buf.length,inetAdd,9092);
			
			
			//创建组播和端口
			MulticastSocket cast = new MulticastSocket();
			//组播消息
			cast.send(packet);
			i++;
			Thread.sleep(500);
			}		
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
	}
}

 

 

package netUDP_组播;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;

/**
 * 接收方
 * @author Administrator
 *
 */
public class AllReceiver {

	public static void main(String[] args) throws InterruptedException {
		
		try {
			//创建组播端口
			MulticastSocket cast = new MulticastSocket(9092);
			
			//创建接收方的地址
			InetAddress InetAdd = InetAddress.getByName("230.0.0.1");
			
			cast.joinGroup(InetAdd);
			while(true){
			//创建接收数据包
			//创建数据缓冲
			byte[] buf = new byte[10];
			DatagramPacket  packet = new DatagramPacket(buf, buf.length);
			System.out.println("等待接收数据>>>>>>");
			cast.receive(packet);
			
			System.out.println(new String(packet.getData()));
			Thread.sleep(500);
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

 

结果;

等待接收数据>>>>>>

0王佳

...........

//分析所有在同一个局域网的客户端都可以收到该消息  ;可以用组播来实现网络监控