理解了Netty的流程后，代码还是比较容易理解的，直接贴出代码

主启动程序：

public class ChatServer {
	private final ChannelGroup group = new DefaultChannelGroup(ImmediateEventExecutor.INSTANCE);
	
	private final EventLoopGroup workerGroup = new NioEventLoopGroup();
	
	private Channel channel;
	
	public ChannelFuture start(InetSocketAddress address){
		ServerBootstrap boot = new ServerBootstrap();
		boot.group(workerGroup).channel(NioServerSocketChannel.class).childHandler(createInitializer(group));
		
		ChannelFuture f = boot.bind(address).syncUninterruptibly();
		channel = f.channel();
		return f;
	}

	protected ChannelHandler createInitializer(ChannelGroup group2) {
		return new ChatServerInitializer(group2);
	}
	
	public void destroy(){
		if(channel != null)
			channel.close();
		group.close();
		workerGroup.shutdownGracefully();
	}
	
	public static void main(String[] args) {
		final ChatServer server = new ChatServer();
		ChannelFuture f = server.start(new InetSocketAddress(2048));
		System.out.println("server start................");
		Runtime.getRuntime().addShutdownHook(new Thread(){
			@Override
			public void run() {
				server.destroy();
			}
		});
		f.channel().closeFuture().syncUninterruptibly();
	}
	
}

初始化链：

public class ChatServerInitializer extends ChannelInitializer<Channel> {

	private final ChannelGroup group;
	public ChatServerInitializer(ChannelGroup group) {
		super();
		this.group = group;
	}

	@Override
	protected void initChannel(Channel ch) throws Exception {
		ChannelPipeline pipeline = ch.pipeline();
		
		pipeline.addLast(new HttpServerCodec());
		
		pipeline.addLast(new ChunkedWriteHandler());
		
		pipeline.addLast(new HttpObjectAggregator(64*1024));
		
		pipeline.addLast(new HttpRequestHandler("/ws"));
		
		pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));
		
		pipeline.addLast(new TextWebSocketFrameHandler(group));
		
	}

}

HTTP请求处理：

public class HttpRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
	
	private final String wsUri;
	public HttpRequestHandler(String wsUri) {
		super();
		this.wsUri = wsUri;
	}
	@Override
	protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest msg)
			throws Exception {
		if(wsUri.equalsIgnoreCase(msg.getUri())){
			ctx.fireChannelRead(msg.retain());
		}else{
			if(HttpHeaders.is100ContinueExpected(msg)){
				FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE);
				ctx.writeAndFlush(response);
			}
			
			RandomAccessFile file = new RandomAccessFile(HttpRequestHandler.class.getResource("/").getPath()+"/index.html", "r");
			HttpResponse response = new DefaultHttpResponse(msg.getProtocolVersion(), HttpResponseStatus.OK);
			response.headers().set(HttpHeaders.Names.CONTENT_TYPE, "text/html;charset=UTF-8");
			
			boolean isKeepAlive = HttpHeaders.isKeepAlive(msg);
			if(isKeepAlive){
				response.headers().set(HttpHeaders.Names.CONTENT_LENGTH, file.length());
				response.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
			}
			
			ctx.write(response);
			if(ctx.pipeline().get(SslHandler.class) == null){
				ctx.write(new DefaultFileRegion(file.getChannel(), 0, file.length()));
			}else{
				ctx.write(new ChunkedNioFile(file.getChannel()));
			}
			
			ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
			if(isKeepAlive == false){
				future.addListener(ChannelFutureListener.CLOSE);
			}
			
			file.close();
		}
	}
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
			throws Exception {
		ctx.close();
		cause.printStackTrace(System.err);
	}
}

websocket处理：

public class TextWebSocketFrameHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
	
	private final ChannelGroup group;
	
	public TextWebSocketFrameHandler(ChannelGroup group) {
		super();
		this.group = group;
	}
	@Override
	public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
			throws Exception {
		
		if(evt == WebSocketServerProtocolHandler.ServerHandshakeStateEvent.HANDSHAKE_COMPLETE){
			ctx.pipeline().remove(HttpRequestHandler.class);
			
			group.writeAndFlush(new TextWebSocketFrame("Client "+ctx.channel()+" joined!"));
			
			group.add(ctx.channel());
		}else{
			super.userEventTriggered(ctx, evt);
		}
		
	}

	@Override
	protected void channelRead0(ChannelHandlerContext ctx,
			TextWebSocketFrame msg) throws Exception {
		group.writeAndFlush(msg.retain());
	}
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
			throws Exception {
		ctx.close();
		cause.printStackTrace();
	}
}

网页index.html代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<script type="text/javascript">
		var socket;
		if (!window.WebSocket) {
			window.WebSocket = window.MozWebSocket;
		}
		if (window.WebSocket) {
			socket = new WebSocket("ws://localhost:2048/ws");
			socket.onmessage = function(event) {
				var ta = document.getElementById(‘responseText‘);
				ta.value = ta.value + ‘\n‘ + event.data
			};
			socket.onopen = function(event) {
				var ta = document.getElementById(‘responseText‘);
				ta.value = "连接开启!";
			};
			socket.onclose = function(event) {
				var ta = document.getElementById(‘responseText‘);
				ta.value = ta.value + "连接被关闭";
			};
		} else {
			alert("你的浏览器不支持！");
		}

		function send(message) {
			if (!window.WebSocket) {
				return;
			}
			if (socket.readyState == WebSocket.OPEN) {
				socket.send(message);
			} else {
				alert("连接没有开启.");
			}
		}
	</script>
	<form onsubmit="return false;">
		<input type="text" name="message" value="http://www.mamicode.com/Hello, World!"><input
			type="button" value="http://www.mamicode.com/发送消息"
			onclick="send(this.form.message.value)">
		<h3>输出：</h3>
		<textarea id="responseText" style="width: 500px; height: 300px;"></textarea>
		<input type="button" onclick="javascript:document.getElementById(‘responseText‘).value=http://www.mamicode.com/‘‘" value="http://www.mamicode.com/清空">
	</form>
</body>
</html>

运行主程序后，在支持Websocket的浏览器中输入 ： 127.0.0.1:2048   就可以打开聊天页面，打开多个页面，可以互相聊天。

项目已经打包上传，

项目地址：https://github.com/ivyboy/nettyWebsocket

Netty4实现Websocket网页间聊天