datagramsclientfile.java

jbuilder2006一书的所有源代码

package datagrams;

import java.io.*;
import java.net.*;

public class DatagramsClientFile {

  public static void main(String[] args) throws IOException {
    //创建DatagramSocket类,用于发送与接收数据包
    DatagramSocket datagramSocket = new DatagramSocket();
    //创建新文件newDemo.jpg
    FileOutputStream fileOutputStream = new FileOutputStream("datagramsDemo.jpg");
    //创建byte数组
    byte[] buf = new byte[1];
    //创建根据服务器名字取得服务器地址的InetAddress类
    InetAddress address = InetAddress.getByName("bemyfriend");
    //创建带有网络地址与端口的数据包
    DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 5557);
    //根据网络地址与端口发送数据包
    datagramSocket.send(packet);
    //设置等待时间为5秒
    datagramSocket.setSoTimeout(5000);
    try{
      while (true) {
        packet = new DatagramPacket(buf, buf.length);
        //接收返回的数据包
        datagramSocket.receive(packet);
        //通过getData()方法获取数据包的数据
        buf = packet.getData();
        //将数据写入文件
        fileOutputStream.write(buf);
      }
    }catch(Exception ex){
      System.out.println("完成数据的接收.");
      fileOutputStream.close();
      //关闭UDP的DatagramScoket接口
      datagramSocket.close();
    }
  }
}