UDP

receive接收端:

public class TestUDPreceive
{
    public static void main(String[] args)
    {
        try
        {
            DatagramSocket ds = new DatagramSocket(3000);
            byte[] buf = new byte[1024];
            DatagramPacket dp = new DatagramPacket(buf , buf.length);
            ds.receive(dp);
            String message = new String(dp.getData(), 0, dp.getLength());
            System.out.println(message);
        }
        catch (SocketException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

send发送端:

public class TestUDPSend
{
    public static void main(String[] args)
    {
        try
        {
            DatagramSocket ds = new DatagramSocket();
            String message = "hello UDP from send";
            //DatagramPacket(字节数组，字节长度，接收地址，端口)
            DatagramPacket dp = new DatagramPacket(message.getBytes(),message.getBytes().length,InetAddress.getByName("127.0.0.1"), 3000);
            ds.send(dp);
        }
        catch (SocketException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}