package cn.itcast_03;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

/*
 * 多次启动接收端:
 *     Unrecognized Windows Sockets error: 0: Cannot bind
 *     端口被占用。
 */
public class ReceiveDemo {
  public static void main(String[] args) throws IOException {
    // 创建接收端Socket对象
    DatagramSocket ds = new DatagramSocket(12345);

    // 创建接收数据包对象
    byte[] bys = new byte[1024];
    DatagramPacket dp = new DatagramPacket(bys, bys.length);

    // 接收数据包
    ds.receive(dp);

    // 解析数据,并显示在控制台
    String ip = dp.getAddress().getHostAddress();
    String s = new String(dp.getData(), 0, dp.getLength());
    System.out.println("from" + ip + " data is:" + s);

    // 释放资源
    ds.close();
  }
}


package cn.itcast_03;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class SedDemo {
  public static void main(String[] args) throws IOException {
    // 创建发送端Socket对象
    DatagramSocket ds = new DatagramSocket();

    // 创建数据,并打包
    byte[] bys = "helloworld".getBytes();
    DatagramPacket dp = new DatagramPacket(bys, bys.length,
        InetAddress.getByName("192.168.31.165"), 12345);

    // 发送数据
    ds.send(dp);

    // 释放资源
    ds.close();

  }
}