[javaSE] 网络编程（UDP通信）

UDP发送端

获取DatagramSocket对象，new出来

获取DatagramPacket对象，new出来，构造参数：byte[]数组，int长度，InetAddress对象，int端口

调用DatagramSocket对象的send()方法，发送出去，参数：DatagramPacket对象

调用DatagramSocket对象的close()方法，关闭资源

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
/**
 * 发送端
 * @author taoshihan
 *
 */
public class Sender {
    public static void main(String[] args) throws Exception {
        DatagramSocket ds=new DatagramSocket();
        byte[] buf="Hello UDP".getBytes();
        DatagramPacket p=new DatagramPacket(buf, buf.length, InetAddress.getLocalHost(),10000);
        ds.send(p);
        ds.close();
    }
}

UDP接收端

获取DatagramSocket对象，new出来，构造参数：int端口号

获取DatagramPacket对象，new出来，构造参数：byte[]数组，int长度

调用DatagramSocket对象的receive()方法，接收数据，参数：DatagramPacket对象

调用DatagramPacket对象的getAddress()方法，获取到InetAdress对象

调用DatagramPacket对象的getData()方法，获取到byte[]字节数组，接收的数据

调用DatagramPacket对象的getLength()方法，获取到数据长度

通过new String()包一下，获得String数据，参数：byte[]数组，0开始，length长度

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
/**
 * 接收端
 * @author taoshihan
 *
 */
public class Receiver {
    public static void main(String[] args) throws Exception {
        DatagramSocket ds=new DatagramSocket(10000);
        byte[] buf=new byte[1024];
        DatagramPacket datagramPacket=new DatagramPacket(buf, buf.length);
        ds.receive(datagramPacket);
        
        InetAddress ip= datagramPacket.getAddress();
        int port=datagramPacket.getPort();
        byte[] resByte=datagramPacket.getData();
        int length=datagramPacket.getLength();
        
        String info=new String(resByte,0,length);
        System.out.println("来自："+ip.getHostAddress()+":"+port+"说："+info);
        
    }
}