简单的udp服务端和客户端
1.服务端的代码。

package udp; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress; /** * UDP服务类 */ public class UdpServerSocket { private byte[] buffer = new byte[1024]; private static DatagramSocket ds = null; private DatagramPacket packet = null; private InetSocketAddress socketAddress = null; /** * 测试方法 */ public static void main(String[] args) throws Exception { String serverHost = "127.0.0.1"; int serverPort = 3344; UdpServerSocket udpServerSocket = new UdpServerSocket(serverHost, serverPort); while (true) { udpServerSocket.receive(); udpServerSocket.response("你好,吃了吗!"); } } /** * 构造函数，绑定主机和端口 */ public UdpServerSocket(String host, int port) throws Exception { socketAddress = new InetSocketAddress(host, port); ds = new DatagramSocket(socketAddress); System.out.println("服务端启动!"); } /** * 接收数据包，该方法会造成线程阻塞 */ public final String receive() throws IOException { packet = new DatagramPacket(buffer, buffer.length); ds.receive(packet); String info = new String(packet.getData(), 0, packet.getLength()); System.out.println("接收信息：" + info); return info; } /** * 将响应包发送给请求端 */ public final void response(String info) throws IOException { System.out.println("客户端地址 : " + packet.getAddress().getHostAddress() + ",端口：" + packet.getPort()); DatagramPacket dp = new DatagramPacket(buffer, buffer.length, packet .getAddress(), packet.getPort()); dp.setData(info.getBytes()); ds.send(dp); } } 2.客户端1.package udp;
2.
3.import java.io.*;
4.import java.net.*;
5.
6./**
7. * UDP客户端程序，用于对服务端发送数据，并接收服务端的回应信息
8. */
9.public class UdpClientSocket {
10. private byte[] buffer = new byte[1024];
11.
12. private static DatagramSocket ds = null;
13.
14. /**
15. * 测试客户端发包和接收回应信息的方法
16. */
17. public static void main(String[] args) throws Exception {
18. UdpClientSocket client = new UdpClientSocket();
19. String serverHost = "127.0.0.1";
20. int serverPort = 3344;
21. client.send(serverHost, serverPort, ("你好，亲爱的!").getBytes());
22. byte[] bt = client.receive();
23. System.out.println("服务端回应数据：" + new String(bt));
24. // 关闭连接
25. try {
26. ds.close();
27. } catch (Exception ex) {
28. ex.printStackTrace();
29. }
30. }
31.
32. /**
33. * 构造函数，创建UDP客户端
34. */
35. public UdpClientSocket() throws Exception {
36. ds = new DatagramSocket(8899); // 邦定本地端口作为客户端
37. }
38.
39. /**
40. * 向指定的服务端发送数据信息
41. */
42. public final void send(final String host, final int port,
43. final byte[] bytes) throws IOException {
44. DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress.getByName(host), port);
45. ds.send(dp);
46. }
47.
48. /**
49. * 接收从指定的服务端发回的数据
50. */
51. public final byte[] receive()
52. throws Exception {
53. DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
54. ds.receive(dp);
55. byte[] data = new byte[dp.getLength()];
56. System.arraycopy(dp.getData(), 0, data, 0, dp.getLength());
57. return data;
58. }
59.}