UDP搭建一个简易的消息发送程序

成事不说，遂事不谏，既往不咎。 --论语·八佾篇

import org.junit.Test;

import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.charset.Charset;


public class DatagramChannelDemo {
    // 发送端
    @Test
    public void sendDatagram() throws Exception {
        // 打开DatagramChannel
        DatagramChannel sendChannel = DatagramChannel.open();
        InetSocketAddress sendAddress = new InetSocketAddress("127.0.0.1", 9999);

        // 发送
        while (true) {
            ByteBuffer buffer = ByteBuffer.wrap("你好，服务器".getBytes("UTF-8"));
            sendChannel.send(buffer, sendAddress);
            System.out.println("已经完成了发送");
            Thread.sleep(1000);
        }
    }

    // 接收端
    @Test
    public void receiveDatagram() throws Exception {
        // 打开DatagramChannel
        DatagramChannel receiveChannel = DatagramChannel.open();
        InetSocketAddress receiveAddress = new InetSocketAddress(9999);
        // 绑定
        receiveChannel.bind(receiveAddress);

        // Buffer
        ByteBuffer receiveBuffer = ByteBuffer.allocate(1024);
        // 接收
        while (true) {
            receiveBuffer.clear();
            SocketAddress socketAddress = receiveChannel.receive(receiveBuffer);

            receiveBuffer.flip();
            System.out.println(socketAddress.toString());
            System.out.println(Charset.forName("UTF-8").decode(receiveBuffer));
        }
    }
}

运行结果：

发送端：

接收端：