datagramsserverstring.java~55~

jbuilder2006一书的所有源代码

package datagrams;

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

public class DatagramsServerString {

  public static void main(String[] args) throws IOException {
    //应用5556端口创建DatagramSocket类
    DatagramSocket datagramSocket = new DatagramSocket(5556);
    try {
      byte[] buf = new byte[20];
      //使用byte数组创建数据包
      DatagramPacket packet = new DatagramPacket(buf, buf.length);
      System.out.println("等待接收数据.");
      //使用DatagramSocket接口接收客户端的数据包,进入等待状态
      datagramSocket.receive(packet);
      String string = "字符串";
      //将字符串转为Bytes()数组
      buf = string.getBytes();
      //根据接收的数据包获取网络地址与端口
      InetAddress address = packet.getAddress();
      int port = packet.getPort();
      //重新创建带有网络地址与端口的数据包
      packet = new DatagramPacket(buf, buf.length, address, port);
      //根据数据包的地址与端口发送数据包
      datagramSocket.send(packet);
      System.out.println("完成数据发送.");
    }
    catch (IOException e) {
      e.printStackTrace();
    }
  }
}