netty学习记录（实例）
使用jar包为netty-all-5.0.0.Alpha1.jar
地址为：http://central.maven.org/maven2/io/netty/netty-all/5.0.0.Alpha1/netty-all-5.0.0.Alpha1.jar
创建一个nettyConfig配置文件，存储整个工程的全局配置
package com.rg2.netty; import io.netty.channel.group.ChannelGroup; import io.netty.channel.group.DefaultChannelGroup; import io.netty.util.concurrent.GlobalEventExecutor; /** * 存储整个工程的全局配置 * @author chengli * */ public class NettyConfig { /** * 存储每一个客户端接入进来时的channel对象 */ public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); }
然后再加上一个 接受/处理/响应客户端websocket请求的核心业务处理类
package com.rg2.netty; import java.util.Date; 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.HttpResponseStatus; import io.netty.handler.codec.http.HttpVersion; 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; /** * 接受/处理/响应客户端websocket请求的核心业务处理类 * @author chengli * */ public class MyWebSocketHandler extends SimpleChannelInboundHandler<Object> { private WebSocketServerHandshaker handshaker; private static final String WEB_SOCKET_URL = "ws://localhost:8888/websocket"; //服务端处理客户端websocket请求的核心方法 @Override protected void messageReceived(ChannelHandlerContext context, Object msg) throws Exception { //处理客户端向服务端发起http握手请求的业务 if(msg instanceof FullHttpRequest){ handHttpRequest(context, (FullHttpRequest)msg); }else if(msg instanceof WebSocketFrame){//处理websocket连接业务 handWebsocketFrame(context, (WebSocketFrame)msg); } } /** * 处理客户端和服务端之前的websocket业务 * @param ctx * @param frame */ private void handWebsocketFrame(ChannelHandlerContext ctx,WebSocketFrame frame){ //判断是否是关闭websocket的指令 if(frame instanceof CloseWebSocketFrame){ handshaker.close(ctx.channel(), (CloseWebSocketFrame)frame.retain()); } //判断是否是ping消息 if(frame instanceof PingWebSocketFrame){ ctx.channel().write(new PongWebSocketFrame(frame.content().retain())); return; } //判断是否是二进制消息，如果是二进制消息，抛出异常 if(!(frame instanceof TextWebSocketFrame)){ System.out.println("目前我们不支持二进制消息"); throw new RuntimeException("【"+this.getClass().getName()+"】不支持消息"); } //返回应答消息 //获取客户端向服务端发送的消息 String request = ((TextWebSocketFrame)frame).text(); System.out.println("服务端收到客户端的消息=====>>"+request); TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString() + ctx.channel().id() + "===>>" + request); //群发，服务端向每个连接上来的客户端群发消息 NettyConfig.group.writeAndFlush(tws); } /** * 处理客户端向服务端发起的http握手请求的业务 * @param ctx * @param req */ private void handHttpRequest(ChannelHandlerContext ctx,FullHttpRequest req){ //netty-all-5.0.0.Alpha2不具有getDecoderResult()方法 if(!req.getDecoderResult().isSuccess()||!("websocket".equals(req.headers().get("Upgrade")))){ sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST)); return; } WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(WEB_SOCKET_URL, null, false); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel()); }else{ handshaker.handshake(ctx.channel(), req); } } /** * 服务端向客户端响应消息 * @param ctx * @param req * @param res */ private void sendHttpResponse(ChannelHandlerContext ctx,FullHttpRequest req,DefaultFullHttpResponse res){ if(res.getStatus().code()!=200){ ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); } //服务端向客户端发送数据 ChannelFuture f = ctx.channel().writeAndFlush(res); if(res.getStatus().code()!=200){ f.addListener(ChannelFutureListener.CLOSE); } } //客户端与服务端创建连接的时候调用 @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { // super.channelActive(ctx); NettyConfig.group.add(ctx.channel()); System.out.println("客户端和服务端连接开启..."); } //客户端与服务端断开连接的时候调用 @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { // super.channelInactive(ctx); NettyConfig.group.remove(ctx.channel()); System.out.println("客户端和服务端连接关闭..."); } //服务端接受客户端发送过来的数据结束之后调用 @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { // super.channelReadComplete(ctx); ctx.flush(); } //工程出现异常的时候调用 @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { // super.exceptionCaught(ctx, cause); cause.printStackTrace(); ctx.close(); } }
要处理 初始化你连接时候的各个组件
package com.rg2.netty; import io.netty.channel.ChannelInitializer; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.http.HttpObjectAggregator; import io.netty.handler.codec.http.HttpServerCodec; import io.netty.handler.stream.ChunkedWriteHandler; /** * 初始化你连接时候的各个组件 * @author chengli * */ public class MyWebSocketChannelHandler extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(SocketChannel e) throws Exception { e.pipeline().addLast("http-codec", new HttpServerCodec()); e.pipeline().addLast("aggregator", new HttpObjectAggregator(65536)); e.pipeline().addLast("http-chunked", new ChunkedWriteHandler()); e.pipeline().addLast("handler", new MyWebSocketHandler()); } }
启动方法：
package com.rg2.netty; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.Channel; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioServerSocketChannel; /** * 程序的入口，负责启动应用 * @author chengli * */ public class Main { public static void main(String[] args) { EventLoopGroup bossGroup = new NioEventLoopGroup(); EventLoopGroup workGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workGroup); b.channel(NioServerSocketChannel.class); b.childHandler(new MyWebSocketChannelHandler()); System.out.println("服务端开启等待客户端连接..."); Channel ch = b.bind(8888).sync().channel(); ch.closeFuture().sync(); } catch (Exception e) { e.printStackTrace(); } finally { //优雅的退出程序 bossGroup.shutdownGracefully(); workGroup.shutdownGracefully(); } } }
静态页面代码
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>WebSocket客户端</title> <script type="text/javascript"> var socket; debugger; if(!window.WebSocket){ window.WebSocket = window.MozWebSocket; } if(window.WebSocket){ socket = new WebSocket("ws://localhost:8888/websocket"); socket.onmessage = function(event){ var ta = document.getElementById("responseContent"); ta.value += event.data + "\r\n"; }; socket.onopen = function(event){ var ta = document.getElementById("responseContent"); ta.value = "您当前的浏览器支持WebSocket，请进行后续操作\r\n"; }; socket.onclose = function(event){ var ta = document.getElementById("responseContent"); ta.value = ""; ta.value = "WebSocket连接已经关闭\r\n"; } }else{ alert("您的浏览器不支持WebSocket"); } 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> </head> <body> <form> <input type="text" name="message" value="" /> <br /> <br /> <input type="submit" value="发送WebSocket请求消息" onclick="send(this.form.message.value)" /> <hr color="#FF0000" /> <h2>客户端接收到服务端返回的应答消息</h2> <textarea id="responseContent" style="width: 1024px;height: 300px;"></textarea> </form> </body> </html>
