通過DatagramSocket類來實現。此類表示用來發送和接收數據報包的套接字。
發送端代碼如下:
2
3 import java.io.IOException; 4 import java.net.*; 5 import java.util.Scanner; 6
7 public class Send implements Runnable{ 8 @Override 9 public void run() { 10 //創建一個發送消息的套接字
11 DatagramSocket sendSocket = null; 12 try { 13 sendSocket = new DatagramSocket(); 14 } catch (SocketException e) { 15 e.printStackTrace(); 16 } 17 while (true) { 18 try { 19 System.out.println("發送端發送消息"); 20 Scanner sc = new Scanner(System.in); 21 String msg = sc.next(); 22
23 byte [] bytes = msg.getBytes();//發送的內容轉化為字節數組
24 InetAddress ip = InetAddress.getByName("192.168.31.169");//接受內容的Ip地址 25
26 //創建要發送的數據包，然后用套接字發送
27 DatagramPacket datagramPacket = new DatagramPacket(bytes,bytes.length,ip,8080); 28 //用套接字發送數據包
29 sendSocket.send(datagramPacket); 30
31 } catch (SocketException e) { 32 e.printStackTrace(); 33 } catch (UnknownHostException e) { 34 e.printStackTrace(); 35 } catch (IOException e) { 36 e.printStackTrace(); 37 } 38 } 39 } 40
41 public static void main(String[] args){ 42 Send s = new Send(); 43 Thread thread = new Thread(s); 44 thread.start(); 45 } 46 }
接收端代碼如下：
2
3 import java.io.IOException; 4 import java.net.DatagramPacket; 5 import java.net.DatagramSocket; 6 import java.net.InetAddress; 7 import java.net.SocketException; 8
9 public class Receive implements Runnable { 10 @Override 11 public void run() { 12 System.out.println("接收端"); 13 //創建接受消息的套接字
14 DatagramSocket receviceSocket = null; 15 try { 16 receviceSocket = new DatagramSocket(8080); 17 } catch (SocketException e) { 18 e.printStackTrace(); 19 } 20 while (true) { 21 try { 22 byte [] bytes = new byte[2048]; 23 //創建一個數據包來接受消息
24 DatagramPacket datagramPacket = new DatagramPacket(bytes,bytes.length); 25 //用套接字接受數據包
26 receviceSocket.receive(datagramPacket); 27 //得到發送端的ip地址對象
28 InetAddress ip = datagramPacket.getAddress(); 29 //將接受到的消息轉換為字符串
30 String rec = new String(datagramPacket.getData()) ; 31 System.out.println(ip.getHostAddress()+"發送的消息為："+rec); 32
33 } catch (SocketException e) { 34 e.printStackTrace(); 35 } catch (IOException e) { 36 e.printStackTrace(); 37 } 38 } 39 } 40
41 public static void main(String[] args) { 42 Receive r = new Receive(); 43 Thread thread = new Thread(r); 44 thread.start(); 45 } 46 }
因為要一直接受消息和發送消息，故用了while循環。
注意事項：發送端的端口要和接收端的端口保持一致。
這里我接受消息的ip地址設置為自己的ip地址來演示實際效果。
