package udptestclient;import java.io.*;import java.net.*;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: </p> * @author not attributable * @version 1.0 */public class ClientService {  public ClientService() {  }  public static void main(String[] args) {    DatagramSocket UDPClientSocket;                DatagramPacket ClientPacket;                InetAddress RemoteHost;                int RemotePort;                byte dataBuf[]=new byte[512];                String Datagram,s;                if(args.length<3)                {                        System.out.println("請輸入本地端口號，遠程服務器主機名，服務器端口號 ！");                        System.exit(0);                }                try{                        UDPClientSocket = new DatagramSocket(                                Integer.parseInt(args[0]));                        RemoteHost = InetAddress.getByName(args[1]);                        RemotePort = Integer.parseInt(args[2]);                        Datagram = new String("This mail is from " +                                InetAddress.getLocalHost().getHostName()                                +" , give me a receipt \n if you can receive it, Thank you! ");                        Datagram.getBytes(0, Datagram.length(),dataBuf,0);                        ClientPacket=new DatagramPacket(dataBuf,512,RemoteHost,RemotePort);                        UDPClientSocket.send(ClientPacket);                        for(int i=0;i<512;i++) dataBuf[i]=0;                        UDPClientSocket.receive(ClientPacket);                        Datagram=new String(ClientPacket.getData());                        System.out.println("從遠程服務器主機 "+args[1]+" 收到如下應答信息：\n");                        System.out.println(Datagram);                        UDPClientSocket.close();                }                catch(Exception e)                {                        System.err.println(e);                }  }}