##创建Server 服务端 ###添加依赖的包
<dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.6.Final</version> </dependency>###创建一个WebSocketServer类 这里主要绑定一个端口的操作
public class WebSocketServer { public void run(int port) throws Exception { EventLoopGroup bossGroup = new NioEventLoopGroup(); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast("http-codec", new HttpServerCodec()); pipeline.addLast("aggregator", new HttpObjectAggregator(65536)); ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler()); pipeline.addLast("handler", new WebSocketServerHandler()); } }); Channel ch = b.bind(port).sync().channel(); System.out.println("Web socket server started at port " + port + '.'); System.out.println("Open your browser and navigate to http://localhost:" + port + '/'); ch.closeFuture().sync(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } public static void main(String[] args) throws Exception { int port = 8088; if (args.length > 0) { try { port = Integer.parseInt(args[0]); } catch (NumberFormatException e) { e.printStackTrace(); } } new WebSocketServer().run(port); } }###创建一个WebSocketServerHandler类 这里是主要写自己业务逻辑的地方
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private static final Logger logger = Logger.getLogger(WebSocketServerHandler.class.getName()); public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); private WebSocketServerHandshaker handshaker; @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { // 传统的HTTP接入 if (msg instanceof FullHttpRequest) { handleHttpRequest(ctx, (FullHttpRequest) msg); } // WebSocket接入 else if (msg instanceof WebSocketFrame) { handleWebSocketFrame(ctx, (WebSocketFrame) msg); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { ctx.flush(); } private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) throws Exception { // 如果HTTP解码失败，返回HHTP异常 if (!req.decoderResult().isSuccess() || (!"websocket".equals(req.headers().get("Upgrade")))) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); return; } // 构造握手响应返回，本机测试 WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory("ws://localhost:8088/websocket", null, false); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel()); } else { handshaker.handshake(ctx.channel(), req); } } private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { // 判断是否是关闭链路的指令 if (frame instanceof CloseWebSocketFrame) { handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain()); return; } // 判断是否是Ping消息 if (frame instanceof PingWebSocketFrame) { ctx.channel().write(new PongWebSocketFrame(frame.content().retain())); return; } // 本例程仅支持文本消息，不支持二进制消息 if (!(frame instanceof TextWebSocketFrame)) { throw new UnsupportedOperationException( String.format("%s frame types not supported", frame.getClass().getName())); } // 返回应答消息 String request = ((TextWebSocketFrame) frame).text(); if (logger.isLoggable(Level.FINE)) { logger.fine(String.format("%s received %s", ctx.channel(), request)); } //currentUserChannel为当前会话通道 Channel currentUserChannel = ctx.channel(); for (Channel channel : channels) { if (channel != currentUserChannel){ channel.writeAndFlush(new TextWebSocketFrame(channel.remoteAddress()+" "+request)); }else { channel.writeAndFlush(new TextWebSocketFrame("我"+" "+request )); } } //ctx.channel().write(new TextWebSocketFrame(request + " , 欢迎使用Netty WebSocket服务，现在时刻：" + new java.util.Date().toString())); } private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) { // 返回应答给客户端 if (res.getStatus().code() != 200) { ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); HttpUtil.setContentLength(res, res.content().readableBytes()); } // 如果是非Keep-Alive，关闭连接 ChannelFuture f = ctx.channel().writeAndFlush(res); if (!HttpUtil.isKeepAlive(req) || res.status().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { // (5) channels.add(ctx.channel()); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { // (6) channels.remove(ctx.channel()); } }###运行WebSocketServer类中的main方法 这时netty服务已经启动了 ##测试 ###用websocket连接服务器进行测试 测试的HTML代码如下：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> Netty WebSocket 时间服务器 </head> <br> <body> <br> <script type="text/javascript"> var socket; if (!window.WebSocket) { window.WebSocket = window.MozWebSocket; } if (window.WebSocket) { socket = new WebSocket("ws://localhost:8088/websocket"); socket.onmessage = function (event) { var ta = document.getElementById('responseText'); //ta.value = ""; ta.value =ta.value +"\n"+ event.data }; socket.onopen = function (event) { var ta = document.getElementById('responseText'); ta.value = "打开WebSocket服务正常，浏览器支持WebSocket!"; }; socket.onclose = function (event) { var ta = document.getElementById('responseText'); ta.value = ""; ta.value = "WebSocket 关闭!"; }; } else { alert("抱歉，您的浏览器不支持WebSocket协议!"); } function send(message) { if (!window.WebSocket) { return; } if (socket.readyState == WebSocket.OPEN) { socket.send(message); } else { alert("WebSocket连接没有建立成功!"); } } </script> <form onsubmit="return false;"> <input type="text" name="message"/> <br><br> <input type="button" value="发送WebSocket请求消息" onclick="send(this.form.message.value)"/> <hr color="blue"/> <h3>服务端返回的应答消息</h3> <textarea id="responseText" style="width:500px;height:300px;"></textarea> </form> </body> </html>运行结果截图：
项目下载地址：https://gitee.com/jingyang3877/all-examples/blob/master/jingyang3877-netty-demo-master.zip
参考博客： https://www.cnblogs.com/carl10086/p/6188808.html http://wiki.jikexueyuan.com/project/netty-4-user-guide/implement-websocket-chat-function.html https://blog.csdn.net/shudaqi2010/article/details/54293000
