DatagramSocket客户端与服务端Java实例

 1 import java.io.IOException;
 2 import java.net.DatagramPacket;
 3 import java.net.DatagramSocket;
 4 import java.net.InetAddress;
 5 
 6 public class TimeClient_UDP{
 7      public static void main(String args[]) throws IOException{
 8          String host = "localhost";
 9          byte[] msg = new byte[256];//存放收发数据
10          InetAddress addr = InetAddress.getByName(host);//获取主机地址
11          System.out.println("侦听主机为:"+addr);
12          DatagramPacket packet = new DatagramPacket(msg,msg.length,addr,3000);//创建要收发的数据报
13          DatagramSocket socket = new DatagramSocket();//创建用于通信的Socket对象
14          socket.send(packet);//发送数据报
15          packet = new DatagramPacket(msg,msg.length);//创建接收的数据报
16          socket.receive(packet);//接收数据报,存放到packet中
17          String time = new String(packet.getData());//获取数据报中的数据内容
18          System.out.println("侦听主机:"+host+"的当前日期为:"+time);
19          socket.close();//释放Socket
20     }
21 }

 1 import java.io.IOException;
 2 import java.net.DatagramPacket;
 3 import java.net.DatagramSocket;
 4 import java.net.InetAddress;
 5 import java.util.Date;
 6 public class TimeServer_UDP{
 7      public static void main(String args[]) throws IOException{
 8           DatagramSocket socket = new DatagramSocket(3000);//Socket对象.端口3000
 9           System.out.println("等待接收数据......");
10           while(true){
11                byte buf[] = new byte[256];
12                DatagramPacket packet = new DatagramPacket(buf,buf.length);
13                socket.receive(packet);
14                
15                InetAddress addr = packet.getAddress();
16                int port = packet.getPort();
17                System.out.println("已接收来自" + addr.toString() + ":"+port+"的数据");
18                
19                String date = new Date().toString();
20                buf = date.getBytes();
21                packet = new DatagramPacket(buf,buf.length,addr,port);
22                socket.send(packet);
23           }
24      }
25 }