Java中使用UDP实现简单的聊天功能

通过DatagramSocket类来实现。此类表示用来发送和接收数据报包的套接字。

发送端代码如下:

 import java.io.IOException;
 import java.net.*;
 import java.util.Scanner;

 public class Send implements Runnable{
     @Override
     public void run() {
         //创建一个发送消息的套接字
         DatagramSocket sendSocket = null;
         try {
             sendSocket = new DatagramSocket();
         } catch (SocketException e) {
             e.printStackTrace();
         }
         while (true) {
             try {
                 System.out.println("发送端发送消息");
                 Scanner sc = new Scanner(System.in);
                 String msg = sc.next();

                 byte [] bytes = msg.getBytes();//发送的内容转化为字节数组
                 InetAddress ip = InetAddress.getByName("192.168.31.169");//接受内容的Ip地址

                 //创建要发送的数据包，然后用套接字发送
                 DatagramPacket datagramPacket = new DatagramPacket(bytes,bytes.length,ip,8080);
                 //用套接字发送数据包
                 sendSocket.send(datagramPacket);

             } catch (SocketException e) {
                 e.printStackTrace();
             } catch (UnknownHostException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
     }

     public static void main(String[] args){
         Send s = new Send();
         Thread thread = new Thread(s);
         thread.start();
     }
 }

接收端代码如下：

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

 public class Receive implements Runnable {
     @Override
     public void run() {
         System.out.println("接收端");
         //创建接受消息的套接字
         DatagramSocket receviceSocket = null;
         try {
             receviceSocket = new DatagramSocket(8080);
         } catch (SocketException e) {
             e.printStackTrace();
         }
         while (true) {
             try {
                 byte [] bytes = new byte[2048];
                 //创建一个数据包来接受消息
                 DatagramPacket datagramPacket = new DatagramPacket(bytes,bytes.length);
                 //用套接字接受数据包
                 receviceSocket.receive(datagramPacket);
                 //得到发送端的ip地址对象
                 InetAddress ip = datagramPacket.getAddress();
                 //将接受到的消息转换为字符串
                 String rec = new String(datagramPacket.getData()) ;
                 System.out.println(ip.getHostAddress()+"发送的消息为："+rec);

             } catch (SocketException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
     }

     public static void main(String[] args) {
         Receive r = new Receive();
         Thread thread = new Thread(r);
         thread.start();
     }
 }

因为要一直接受消息和发送消息，故用了while循环。

注意事项：发送端的端口要和接收端的端口保持一致。　　

这里我接受消息的ip地址设置为自己的ip地址来演示实际效果。