Netty WebSocket 开发
代码:
Server
package netty.protocol.websocket.server; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.Channel; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.handler.codec.http.HttpObjectAggregator; import io.netty.handler.codec.http.HttpServerCodec; import io.netty.handler.stream.ChunkedWriteHandler; /** * TODO * * @description * @author ez * @time 2015年6月3日 下午4:42:31 */ 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(); /* * HttpServerCodec ,将请求和应答消息编码或者解码为HTTP消息 */ pipeline.addLast("http-codec", new HttpServerCodec()); /* * HttpObjectAggregator , * 将HTTP消息的多个部分组合成一条完整的HTTP消息; */ pipeline.addLast("aggregator", new HttpObjectAggregator(65536)); /* * ChunkedWriteHandler , * 的主要作用是支持异步发送大的码流(例如大文件传输),但不占用过多的内存,防止JAVA内存溢出 */ ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler()); /* * WebSocketServerHandler 自己的业务处理 */ 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 = 8080; if (args.length > 0) { try { port = Integer.parseInt(args[0]); } catch (NumberFormatException e) { e.printStackTrace(); } } new WebSocketServer().run(port); } }
Handler
package netty.protocol.websocket.server; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpHeaders.setContentLength; import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame; import io.netty.handler.codec.http.websocketx.PingWebSocketFrame; import io.netty.handler.codec.http.websocketx.PongWebSocketFrame; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory; import io.netty.util.CharsetUtil; import java.util.logging.Level; import java.util.logging.Logger; /** * TODO * * @description * @author ez * @time 2015年6月3日 下午4:42:59 */ public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private static final Logger logger = Logger .getLogger(WebSocketServerHandler.class.getName()); private WebSocketServerHandshaker handshaker; @Override public void messageReceived(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.getDecoderResult().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:8080/websocket", null, false); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory .sendUnsupportedWebSocketVersionResponse(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)); } ctx.channel().writeAndFlush( new TextWebSocketFrame(request + " , 欢迎使用Netty WebSocket服务，现在时刻：" + new java.util.Date().toString())); for (int i = 0; i < 100; i++) { ctx.channel().writeAndFlush( new TextWebSocketFrame(request + i + new java.util.Date().toString())); try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } 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(); setContentLength(res, res.content().readableBytes()); } // 如果是非Keep-Alive，关闭连接 ChannelFuture f = ctx.channel().writeAndFlush(res); if (!isKeepAlive(req) || res.getStatus().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } }
html
<!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:8080/websocket"); socket.onmessage = function(event) { var ta = document.getElementById('responseText'); ta.value += 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" value="Netty最佳实践"/> <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>
