c14_8.java

这是java网络编程的8个比较典型的实例

//UDP 客户端程序
import java.io.*;
import java.net.*;
import java.util.*;
class c14_8{
  public static void main(String[] args) {
     DatagramSocket socket;//用于发送接受UDP
     DatagramPacket packet;//用于保存UDP的内容
     InetAddress address;
     int port;
     byte[] buf=new byte[1000];
     String s="Hello,server!";
      if(args.length<3)
      {
        System.out.println("输入本地端口号,服务器名,服务器端口号 ");
        System.exit(0);
      }
     try {
       socket=new DatagramSocket(Integer.parseInt(args[0]));
       address=InetAddress.getByName(args[1]);
       port=Integer.parseInt(args[2]);
       s.getBytes(0,s.length(),buf,0);
       packet=new DatagramPacket(buf,buf.length,address,port);
       socket.send(packet);  //向服务器发送packet
       for(int i=0;i<buf.length;i++)buf[i]=0;
       packet=new DatagramPacket(buf,buf.length); // 生成接收的packet
       socket.receive(packet);  //接收服务器传来的packet
       s= new String(packet.getData());
       System.out.println("Received from server: "+s); // 打印packet内容
       socket.close();  // 关闭 socket
      }catch(Exception e) {
          System.out.println("Error:"+e);
         }
     }
  }