要求：
使用UDP协议实现一个聊天程序代码：
发送端：
package UDP聊天程序; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; import java.net.UnknownHostException; import java.util.Scanner; public class Send { public static void main(String[] args) { System.out.println("发送端已启动！"); DatagramSocket socket=null; Scanner scanner=new Scanner(System.in); try { //1.创建Datagramsocket对象 socket=new DatagramSocket(); while(true){ //2.要发送的数据 String string=scanner.nextLine(); //3.创建数据包 DatagramPacket packet=new DatagramPacket(string.getBytes(), string.getBytes().length,InetAddress.getLocalHost(),6666); //4.发送数据 socket.send(packet); //若我方发送了bye，马上结束聊天 if(string.equals("bye")){ System.out.println("bye,聊天结束！"); break; } //5.接收--接收端回复的数据 byte[] bs=new byte[1024]; DatagramPacket packet2=new DatagramPacket(bs, bs.length); socket.receive(packet2); String string2=new String(packet2.getData(), 0, packet2.getLength()); //若对方发送了bye，马上结束聊天 if(string2.equals("bye")){ System.out.println("bye,聊天结束！"); break; } System.out.println("接收端回复："+string2); } } catch (SocketException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnknownHostException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(socket!=null){ socket.close(); } } } }接收端：
package UDP聊天程序; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; import java.util.Scanner; public class Receive { public static void main(String[] args) { System.out.println("接收端已启动！"); DatagramSocket socket=null; Scanner scanner=new Scanner(System.in); try { //1.创建Datagrams对象 socket=new DatagramSocket(6666); while(true){ //2.创建数据包packet byte[] buf=new byte[1024]; DatagramPacket packet=new DatagramPacket(buf, buf.length); //3.接收数据 socket.receive(packet); String string=new String(packet.getData(), 0, packet.getLength()); //若对方发送了bye，马上结束聊天 if(string.equals("bye")){ System.out.println("bye,聊天结束！"); break; } System.out.println("发送端说："+string); //4.给发送端回复 String string2=scanner.nextLine(); DatagramPacket packet2=new DatagramPacket(string2.getBytes(), string2.getBytes().length,packet.getAddress(),packet.getPort()); socket.send(packet2); //若我方发送了bye，马上结束聊天 if(string2.equals("bye")){ System.out.println("bye,聊天结束！"); break; } } } catch (SocketException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(socket!=null){ socket.close(); } } } }运行结果：
接收端聊天列表：
发送端聊天列表：
