Netty UDP通信Demo

1.服务端代码

package udp;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.DatagramPacket;
import io.netty.channel.socket.nio.NioDatagramChannel;

public class UdpServer {

public static void main(String[] args) {
    try {
        Bootstrap b = new Bootstrap();
        EventLoopGroup group = new NioEventLoopGroup();
        b.group(group)
                .channel(NioDatagramChannel.class)
                .option(ChannelOption.SO_BROADCAST, true)
                .handler(new UdpServerHandler());

        b.bind(2555).sync().channel().closeFuture().await();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

private static class UdpServerHandler extends SimpleChannelInboundHandler {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        ByteBuf buf = packet.copy().content();
        byte[] req = new byte[buf.readableBytes()];
        buf.readBytes(req);
        String body = new String(req, "UTF-8");
        System.out.println(body);//打印收到的信息
        //向客户端发送消息
        String json = "来自服务端: 南无阿弥陀佛";
        // 由于数据报的数据是以字符数组传的形式存储的，所以传转数据
        byte[] bytes = json.getBytes("UTF-8");
        DatagramPacket data = new DatagramPacket(Unpooled.copiedBuffer(bytes), packet.sender());
        ctx.writeAndFlush(data);//向客户端发送消息
    }
}

}

2.客户端代码

package udp;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.DatagramPacket;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.util.CharsetUtil;

import java.net.InetSocketAddress;

public class UdpClient {

public static final int MessageReceived = 0x99;
private static int scanPort = 2555;

public UdpClient(int scanPort) {
    this.scanPort = scanPort;
}


private static class CLientHandler extends SimpleChannelInboundHandler {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        String body = packet.content().toString(CharsetUtil.UTF_8);
        System.out.println(body);
    }
}

public static void main(String[] args) {

    EventLoopGroup group = new NioEventLoopGroup();
    try {
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioDatagramChannel.class)
                .handler(new CLientHandler());

        Channel ch = b.bind(0).sync().channel();

        ch.writeAndFlush(new DatagramPacket(
                Unpooled.copiedBuffer("来自客户端:南无本师释迦牟尼佛", CharsetUtil.UTF_8),
                new InetSocketAddress("127.0.0.1", scanPort))).sync();

        ch.closeFuture().await();

    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        group.shutdownGracefully();
    }
}

}

3.分别启动