UDP传输

• 1.发送Send
  • 创建DatagramSocket, 随机端口号
  • 创建DatagramPacket, 指定数据, 长度, 地址, 端口
  • 使用DatagramSocket发送DatagramPacket
  • 关闭DatagramSocket
• 2.接收Receive
  • 创建DatagramSocket, 指定端口号
  • 创建DatagramPacket, 指定数组, 长度
  • 使用DatagramSocket接收DatagramPacket
  • 关闭DatagramSocket
  • 从DatagramPacket中获取数据
• 3.接收方获取ip和端口号
  • String ip = packet.getAddress().getHostAddress();
  • int port = packet.getPort();

 

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UDP传输优化

• 接收端Receive

• DatagramSocket socket = new DatagramSocket(6666);                       //创建socket相当于创建码头
  DatagramPacket packet = new DatagramPacket(new byte[1024], 1024);       //创建packet相当于创建集装箱
  
  while(true) {
      socket.receive(packet);                                             //接收货物
       byte[] arr = packet.getData();
      int len = packet.getLength();
      String ip = packet.getAddress().getHostAddress();
      System.out.println(ip + ":" + new String(arr,0,len));
  }
  

• 发送端Send

  DatagramSocket socket = new DatagramSocket();       //创建socket相当于创建码头
  Scanner sc = new Scanner(System.in);
  
  while(true) {
      String str = sc.nextLine();
      if("quit".equals(str))
          break;
      DatagramPacket packet =                             //创建packet相当于创建集装箱
              new DatagramPacket(str.getBytes(), str.getBytes().length, InetAddress.getByName("127.0.0.1"), 6666);
      socket.send(packet);            //发货
  }
  socket.close();
  

 

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UDP传输多线程

发送和接收在一个窗口完成

public class Demo_MoreThread {

    /**
     * @param args
     */
    public static void main(String[] args) {
        new Receive().start();

        new Send().start();
    }

}

class Receive extends Thread {
    public void run() {
        try {
            DatagramSocket socket = new DatagramSocket(6666);                   //创建socket相当于创建码头
            DatagramPacket packet = new DatagramPacket(new byte[1024], 1024);   //创建packet相当于创建集装箱

            while(true) {
                socket.receive(packet);                                             //接收货物
                byte[] arr = packet.getData();
                int len = packet.getLength();
                String ip = packet.getAddress().getHostAddress();
                System.out.println(ip + ":" + new String(arr,0,len));
            }
        } catch (IOException e) {

            e.printStackTrace();
        }
    }
}

class Send extends Thread {
    public void run() {
        try {
            DatagramSocket socket = new DatagramSocket();       //创建socket相当于创建码头
            Scanner sc = new Scanner(System.in);

            while(true) {
                String str = sc.nextLine();
                if("quit".equals(str))
                    break;
                DatagramPacket packet =                             //创建packet相当于创建集装箱
                        new DatagramPacket(str.getBytes(), str.getBytes().length, InetAddress.getByName("127.0.0.1"), 6666);
                socket.send(packet);            //发货
            }
            socket.close();
        }  catch (IOException e) {

            e.printStackTrace();
        }
    }
}