Netty结合webSocket做聊天案例

时间 2021-07-13 标签 netty聊天 netty-webSocket netty

Netty的介绍就不在这里阐述了,前面也写过关于Netty的文章:

这里不做过多的介绍,代码里有相应的注释,

首先添加依赖:

<dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.21.Final</version>
        </dependency>

WebsocketServer

@Component
public class WebsocketServer {

    private final static Logger LOGGER = LoggerFactory.getLogger(WebsocketServer.class);
    //初始化主线程(boss线程)
    NioEventLoopGroup mainGroup = new NioEventLoopGroup();
    //初始化从线程池(work线程)
    NioEventLoopGroup subGroup = new NioEventLoopGroup();

    @PostConstruct
    public void start() {
        try {
            //创建服务启动器
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            //指定使用主线程和从线程
            serverBootstrap.group(mainGroup, subGroup)
                    //指定使用NIO通道类型
                    .channel(NioServerSocketChannel.class)
                    .localAddress(new InetSocketAddress(9001))
                    //保持长连接
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    //指定通道初始化器用来加载当Channel收到事件消息后,如何进行业务处理
                    .childHandler(new WsServerInitializer());
            //绑定端口启动服务器,并等待服务启动
            ChannelFuture future = serverBootstrap.bind().sync();
            if (future.isSuccess()) {
                LOGGER.info("启动 Netty 成功");
            }
            //等待服务器关闭
            //future.channel().closeFuture().sync();

            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    /** * 销毁 */
    @PreDestroy
    public void destroy() {
        mainGroup.shutdownGracefully().syncUninterruptibly();
        subGroup.shutdownGracefully().syncUninterruptibly();
        LOGGER.info("关闭 Netty 成功");
    }
}

WsServerInitializer(通道初始化)

/** * Created by haoxy on 2019/1/4. * E-mail:[email protected] * github:https://github.com/haoxiaoyong1014 * 通道初始化器 * 用来加载通道处理器 */
public class WsServerInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        //用于支持 http协议
        //websocket 基于http协议,需要 http的编码器
        pipeline.addLast(new HttpServerCodec())
                //对大数据流的支持
                .addLast(new ChunkedWriteHandler())
                //添加对HTTP请求和响应的聚合器: 只要Netty进行编码都需要使用
                //对HttpMessage进行聚合,聚合成FullHttpRequest获取FullHttpResponse
                .addLast(new HttpObjectAggregator(1024 * 64))

                //-----------支持 webSocket----------
                //需要指定接收请求的路由,处理握手动作(close,ping pong),ping+pong=心跳
                //必须使用 ws 后缀结尾的 url 才能访问
                .addLast(new WebSocketServerProtocolHandler("/ws"))
                //添加自定义的 handler
                .addLast(new ChatHandler());
    }
}

ChatHandler(自定义业务处理类)

/** * Created by haoxy on 2019/1/4. * E-mail:[email protected] * github:https://github.com/haoxiaoyong1014 */
//TextWebSocketFrame 在 netty 中是用于webSocket专门处理文本对象,frame是消息的载体.
public class ChatHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {


    private final static Logger LOGGER = LoggerFactory.getLogger(ChatHandler.class);

    //用于记录和管理所有客户端的Channel

    private static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd hh:MM");

    //当接收到客户端发过来的消息就会触发此回调
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception {
        String content = textWebSocketFrame.text();
        System.out.println("接收到的数据: " + content);
        //将消息发给其他客户端排除自己

        Channel channel = channelHandlerContext.channel();
        for (Channel ch : channels) {
            //排除当前通道
            if (channel != ch) {
                ch.writeAndFlush(new TextWebSocketFrame(sdf.format(new Date()) + ":" + content));
            }
        }

        /*//将接收的消息发送所有的客户端 for (Channel channel : channels) { channel.writeAndFlush(new TextWebSocketFrame(sdf.format(new Date()) + ":" + content)); }*/
    }

    //当有新的客户端连接服务器之后,就会自动调用这个方法
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        channels.add(ctx.channel());

    }

}

chat.html(前端代码)

<body>
<input type="text" id="message">
<input type="button" value="发送消息" onclick="sendMsg()">
<br/>
接收到消息:
<p id="server_message" style="background-color: #AAAAAA"></p>

<script> var websocket = null; //判断当前浏览器是否支持 webSocket if (window.WebSocket) { websocket = new WebSocket("ws://127.0.0.1:9001/ws"); websocket.onopen = function (ev) { console.log("建立连接"); } websocket.onclose = function (ev) { console.log("断开连接"); } websocket.onmessage = function (ev) { console.log("接收到服务器的消息" + ev.data); var server_message = document.getElementById("server_message"); server_message.innerHTML += ev.data + "<br/>"; } } else { alert("当前浏览器不支持 webSocket") } function sendMsg() { var message = document.getElementById("message"); websocket.send(message.value) } </script>
</body>

案例效果图:

窗口A给窗口B发送消息:

窗口B回复窗口A的消息:

案例项目地址:

netty-chat