udpclient.java

JAVA网络学习例题

  //UdpClient.java
  import java.io.*;
  import java.net.*; 
  
  public class UdpClient { 
  
  public void go() throws IOException, UnknownHostException { 
  DatagramSocket datagramSocket; 
  //向服务器发送的数据包
  DatagramPacket outDataPacket; 
  //从服务器得到的数据包
  DatagramPacket inDataPacket;
  //服务器主机的地址
  InetAddress serverAddress; 
  //缓冲空间
  byte[] msg = new byte[100];
  //接收到的字符串信息
  String receivedMsg; 
  
  //生成一个可以接受发送数据的套接字 
  datagramSocket = new DatagramSocket(); 
  
  //服务器运行在本机，如果找不到服务器，则抛出“无法找到服务器”的异常
  serverAddress = InetAddress.getLocalHost(); 
  
  //设置一个向服务器发送的数据请求
  //发送端口是8000端口
  outDataPacket = new DatagramPacket(msg, 1, serverAddress, 8000); 
  
  //向服务器发送数据请求
  datagramSocket.send(outDataPacket); 
  
  //设置一个从服务器接受的数据请求
  inDataPacket = new DatagramPacket(msg, msg.length); 
  
  //从服务器得到时间
  datagramSocket.receive(inDataPacket); 
  
  //将接收到的数据打印在屏幕上 
  receivedMsg = new String 
  (inDataPacket.getData(), 0, inDataPacket.getLength()); 
  System.out.println(receivedMsg); 
  
  //关闭套接字
  datagramSocket.close(); 
  } 
  
  //主函数
  public static void main(String args[]) { 
  UdpClient udpClient = new UdpClient(); 
  try { 
  udpClient.go(); 
  } catch (Exception e) { 
  System.out.println ("Exception occured with socket."); 
  System.out.println (e); 
  System.exit(1); 
  } 
  } 
  }