DatagramSocket(UDP协议)

一、UDP协议无状态协议，不可靠协议，单向通信，数据包

广播方：

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

public class Broadcast {

    public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
        DatagramSocket ds=new DatagramSocket();
        InetAddress address=InetAddress.getByName("123.123.123.123");//输入本服务器IP
        byte [] bs="广播一条通知：".getBytes();
        DatagramPacket dp=new DatagramPacket(bs, bs.length,address,6666);//端口号自定义
        ds.send(dp);
        ds.close();
    }
}

听众方：

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.sql.SQLException;
public class UDPClient {

    public static void main(String[] args)  throws IOException{
        DatagramSocket ds=new DatagramSocket(6666);
        byte[] bs=new byte[65536];
        DatagramPacket dp=new DatagramPacket(bs, bs.length);
        ds.receive(dp);
        String s=new String(dp.getData());
        System.out.println("收到的数据为："+s.substring(0,dp.getLength()/2)+";收到的位移偏量为："+dp.getOffset()+";有效长度为："+dp.getLength());
        
    }
}