Netty5 + WebSocket 练习

2023-08-16 20:14:16

1. 了解WebSocket知识
　　略
2. websocket实现系统简单反馈时间

　　WebSocketServerHandler.java

 package com.jieli.nettytest.websocketserver;

 import io.netty.bootstrap.ServerBootstrap;

 import io.netty.channel.ChannelFuture;

 import io.netty.channel.ChannelInitializer;

 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;

 public class WebSocketServer {

     public void run(int port){

         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 {

                     //HttpServerCodec将请求和应答消息编码或解码为HTTP消息

                     //通常接收到的http是一个片段，如果想要完整接受一次请求所有数据，我们需要绑定HttpObjectAggregator

                     //然后就可以收到一个FullHttpRequest完整的请求信息了

                     //ChunkedWriteHandler 向客户端发送HTML5文件，主要用于支持浏览器和服务器进行WebSocket通信

                     //WebSocketServerHandler自定义Handler

                     ch.pipeline().addLast("http-codec", new HttpServerCodec())

                                  .addLast("aggregator", new HttpObjectAggregator(65536)) //定义缓冲大小

                                  .addLast("http-chunked", new ChunkedWriteHandler())

                                  .addLast("handler", new WebSocketServerHandler());

                 }

             });

             ChannelFuture f = b.bind(port).sync();

             System.out.println("start...");

             f.channel().closeFuture().sync();

         } catch (Exception e) {

             e.printStackTrace();

         } finally {

             workerGroup.shutdownGracefully();

             bossGroup.shutdownGracefully();

         }

     }

     public static void main(String[] args) {

         new WebSocketServer().run(7777);

     }

 }

　　WebSocketServerHandler.java

 package com.jieli.nettytest.websocketserver;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 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.HttpHeaderUtil;

 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;

 public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object>{

     /**

      * 日志

      */

     private static final Logger logger =

             Logger.getLogger(WebSocketServerHandler.class.getName());

     /**

      * 全局websocket

      */

     private WebSocketServerHandshaker handshaker;

     @Override

     protected void messageReceived(ChannelHandlerContext ctx, Object msg)

             throws Exception {

         //普通HTTP接入

         if(msg instanceof FullHttpRequest){

             handleHttpRequest(ctx, (FullHttpRequest) msg);

         }else if(msg instanceof WebSocketFrame){ //websocket帧类型 已连接

             //BinaryWebSocketFrame CloseWebSocketFrame ContinuationWebSocketFrame

             //PingWebSocketFrame PongWebSocketFrame TextWebScoketFrame

             handleWebSocketFrame(ctx, (WebSocketFrame) msg);

         }

     }

     @Override

     public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

         ctx.flush();

     }

     private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest request){

         //如果http解码失败 则返回http异常 并且判断消息头有没有包含Upgrade字段(协议升级)

         if(!request.decoderResult().isSuccess()

                 || (!"websocket".equals( request.headers().get("Upgrade")))    ){

             sendHttpResponse(ctx, request, new DefaultFullHttpResponse(

                     HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));

             return ;

         }

         //构造握手响应返回

         WebSocketServerHandshakerFactory ws = new WebSocketServerHandshakerFactory("", null, false);

         handshaker = ws.newHandshaker(request);

         if(handshaker == null){

             //版本不支持

             WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());

         }else{

             handshaker.handshake(ctx.channel(), request);

         }

     }

     /**

      * websocket帧

      * @param ctx

      * @param frame

      */

     private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){

         //判断是否关闭链路指令

         if(frame instanceof CloseWebSocketFrame){

             handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());

             return ;

         }

         //判断是否Ping消息 -- ping/pong心跳包

         if(frame instanceof PingWebSocketFrame){

             ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));

             return ;

         }

         //本程序仅支持文本消息， 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 text文本帧

         String request = ((TextWebSocketFrame) frame).text();

         //打印日志

         if(logger.isLoggable(Level.FINE)){

             logger.fine(String.format("%s received %s", ctx.channel(), request));

         }

         //发送到客户端websocket

         ctx.channel().write(new TextWebSocketFrame(request

                 + ", 欢迎使用Netty WebSocket服务， 现在时刻:"

                 + new java.util.Date().toString()));

     }

     /**

      * response

      * @param ctx

      * @param request

      * @param response

      */

     private static void sendHttpResponse(ChannelHandlerContext ctx,

             FullHttpRequest request, FullHttpResponse response){

         //返回给客户端

         if(response.status().code() != HttpResponseStatus.OK.code()){

             ByteBuf buf = Unpooled.copiedBuffer(response.status().toString(), CharsetUtil.UTF_8);

             response.content().writeBytes(buf);

             buf.release();

             HttpHeaderUtil.setContentLength(response, response.content().readableBytes());

         }

         //如果不是keepalive那么就关闭连接

         ChannelFuture f = ctx.channel().writeAndFlush(response);

         if(!HttpHeaderUtil.isKeepAlive(response)

                 || response.status().code() != HttpResponseStatus.OK.code()){

             f.addListener(ChannelFutureListener.CLOSE);

         }

     }

     /**

      * 异常 出错

      */

     @Override

     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)

             throws Exception {

         cause.printStackTrace();

         ctx.close();

     }

 }

　　WebSocketServer.html (这个随便放都可以，到时候双击打开这个即可，不由服务器提供)

 <html>

     <head>

         <meta charset="utf-8">

         <title>Netty websocket 时间服务器</title>

     </head>

     <body>

         <form action="" onsubmit="return false;">

             <input type="text" name="message" value="..."/>

             <br>

             <input type="button" value="send" value="发送websocket请求消息" onclick="send(this.form.message.value);" />

             <hr color="blue">

             <h3>服务器返回信息</h3>

             <textarea id="responseText" rows="10" cols=""></textarea>

         </form>

     </body>

     <script type="text/javascript">

         var socket;

         if(!window.WebSocket){

             window.WebSocket = window.MozWebSocket;

         }

         if(window.WebSocket){

             socket = new WebSocket("ws://localhost:7777/websocket");

             socket.onmessage = function(event){

                 var ta = document.getElementById('responseText');

                 ta.value="";

                 ta.value=event.data;

             };

             socket.onopen = function(event){

                 var ta = document.getElementById('responseText');

                 ta.value = "打开websocket服务正常";

             }

             socket.onclose = function(event){

                 var ta = document.getElementById('responseText');

                 ta.value="";

                 ta.value="websocket关闭";

             }

         }else{

             alert("对不起，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 连接创建失败.");

             }

         }

     </script>

 </html>

　　运行结果

Netty5 + WebSocket 练习

Netty5 + WebSocket 练习

3. websocket实现简单聊天室

　　WebSocketChatServer.java

 package com.jieli.nettytest.websocket;

 import io.netty.bootstrap.ServerBootstrap;

 import io.netty.channel.ChannelFuture;

 import io.netty.channel.ChannelOption;

 import io.netty.channel.EventLoopGroup;

 import io.netty.channel.nio.NioEventLoopGroup;

 import io.netty.channel.socket.nio.NioServerSocketChannel;

 public class WebsocketChatServer {

     private int port;

     public WebsocketChatServer(int port){

         this.port = port;

     }

     public void run() throws Exception{

         EventLoopGroup bossGroup = new NioEventLoopGroup();

         EventLoopGroup workerGroup = new NioEventLoopGroup();

         try {

             ServerBootstrap b = new ServerBootstrap();

             b.group(bossGroup, workerGroup)

              .channel(NioServerSocketChannel.class)

              .childHandler(new WebsocketChatServerInitializer())

              .option(ChannelOption.SO_BACKLOG, 128)

              .childOption(ChannelOption.SO_KEEPALIVE, true);

             System.out.println("websocket start..");

             ChannelFuture f = b.bind(port).sync();

             f.channel().closeFuture().sync();

         } catch (Exception e) {

             e.printStackTrace();

         } finally {

             workerGroup.shutdownGracefully();

             bossGroup.shutdownGracefully();

             System.out.println("websocket close.");

         }

     }

     public static void main(String[] args) throws Exception{

         new WebsocketChatServer(8080).run();

     }

 }

　　WebsocketChatServerInitializer.java

 package com.jieli.nettytest.websocket;

 import io.netty.channel.ChannelInitializer;

 import io.netty.channel.ChannelPipeline;

 import io.netty.channel.socket.SocketChannel;

 import io.netty.handler.codec.http.HttpObjectAggregator;

 import io.netty.handler.codec.http.HttpServerCodec;

 import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;

 import io.netty.handler.stream.ChunkedWriteHandler;

 public class WebsocketChatServerInitializer extends ChannelInitializer<SocketChannel>{

     @Override

     protected void initChannel(SocketChannel ch) throws Exception {

         ChannelPipeline pipeline = ch.pipeline();

         pipeline.addLast(new HttpServerCodec())

                 .addLast(new HttpObjectAggregator(64*1024))

                 .addLast(new ChunkedWriteHandler())

                 .addLast(new HttpRequestHandler("/ws")) //如果访问的是RUI"/ws"，处理WebSocket升级

                 .addLast(new WebSocketServerProtocolHandler("/ws"))

                 .addLast(new TextWebSocketFrameHandler());

     }

 }

　　HttpRequestHandler.java

 package com.jieli.nettytest.websocket;

 import java.io.File;

 import java.io.RandomAccessFile;

 import java.net.URL;

 import io.netty.channel.Channel;

 import io.netty.channel.ChannelFuture;

 import io.netty.channel.ChannelFutureListener;

 import io.netty.channel.ChannelHandlerContext;

 import io.netty.channel.DefaultFileRegion;

 import io.netty.channel.SimpleChannelInboundHandler;

 import io.netty.handler.codec.http.DefaultHttpResponse;

 import io.netty.handler.codec.http.FullHttpRequest;

 import io.netty.handler.codec.http.FullHttpResponse;

 import io.netty.handler.codec.http.HttpHeaderNames;

 import io.netty.handler.codec.http.HttpHeaderUtil;

 import io.netty.handler.codec.http.HttpHeaderValues;

 import io.netty.handler.codec.http.HttpResponse;

 import io.netty.handler.codec.http.HttpResponseStatus;

 import io.netty.handler.codec.http.HttpVersion;

 import io.netty.handler.codec.http.LastHttpContent;

 import io.netty.handler.ssl.SslHandler;

 import io.netty.handler.stream.ChunkedNioFile;

 public class HttpRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest>{

     //扩展SimpleChannelInboundHandler用于处理FullHttpRequest信息

     private final String wsuri;

 //    private static final File index;

 //

 //    static {

 //        URL location = HttpRequestHandler.class

 //                .getProtectionDomain().getCodeSource().getLocation();

 //        try {

 //            String path = location.toURI() + "html/index.html";

 //            path = !path.contains("file:") ? path : path.substring(5);

 //            index = new File(path);

 //        } catch (Exception e) {

 //            e.printStackTrace();

 //            throw new IllegalStateException("can't find index.html");

 //        }

 //    }

     public HttpRequestHandler(String wsuri){

         this.wsuri = wsuri;

     }

     @Override

     protected void messageReceived(ChannelHandlerContext ctx,

             FullHttpRequest request) throws Exception {

         if(wsuri.equalsIgnoreCase(request.uri())){

             //如果请求的是WebSocket升级，将其传递给在ChannelPipeline中的下一个ChannelInboundHandler处理

             //这里跟第一个例子的websocket协议升级判断方式是不同的 因为只只是判断uri路径而已

             //对应的js请求路径 socket = new WebSocket("ws://localhost:8080/ws");

             ctx.fireChannelRead(request.retain());

         }else{

             //处理100continue

             if(HttpHeaderUtil.is100ContinueExpected(request)){

                 send100Continue(ctx);

             }

             //读取默认页

             RandomAccessFile file = new RandomAccessFile("C:\\html\\index.html", "r");

             HttpResponse response = new DefaultHttpResponse(

                     request.protocolVersion(), HttpResponseStatus.OK);

             response.headers().set(HttpHeaderNames.CONTENT_TYPE,

                     "text/html; charset=UTF-8");

             boolean keepAlive = HttpHeaderUtil.isKeepAlive(request);

             if(keepAlive){

                 response.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, (int) file.length());

                 response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);

             }

             ctx.write(response);

             if(ctx.pipeline().get(SslHandler.class) == null){

                 //如果不是https安全连接的话 要达到最大效率的话，可以通过把index.html直接存储在DefaultFileRegion中

                 //实现零拷贝传输 就是不拷贝到内存，直接读取文件通过文件输出流进行处理

                 ctx.write(new DefaultFileRegion(file.getChannel(), 0, file.length()));

             }else{

                 //否则要读取全部文件，然后处理加密，在发送，只不过这一切都有netty内部处理

                 //A ChunkedInput that fetches data from a file chunk by chunk using NIO FileChannel.

                 //If your operating system supports zero-copy file transfer such as sendfile(),

                 //you might want to use FileRegion instead.

                 ctx.write(new ChunkedNioFile(file.getChannel()));

             }

             ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);

             if(!keepAlive){

                 future.addListener(ChannelFutureListener.CLOSE);

             }

             file.close();

         }

     }

     private static void send100Continue(ChannelHandlerContext ctx){

         FullHttpResponse response = (FullHttpResponse) new DefaultHttpResponse(

                 HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE);

         ctx.writeAndFlush(response);

     }

     @Override

     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)

             throws Exception {

         Channel incoming = ctx.channel();

         System.out.println("Client:"+incoming.remoteAddress()+"exception.");

         cause.printStackTrace();

         ctx.close();

     }

 }

　　html/index.html

 <!DOCTYPE html>

 <html>

 <head>

 <meta charset="UTF-8">

 <title>WebSocket Chat</title>

 </head>

 <body>

     <script type="text/javascript">

         var socket;

         if (!window.WebSocket) {

             window.WebSocket = window.MozWebSocket;

         }

         if (window.WebSocket) {

             socket = new WebSocket("ws://localhost:8080/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 WebSocket！");

         }

         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;">

         <h3>WebSocket 聊天室：</h3>

         <textarea id="responseText" style="width: 500px; height: 300px;"></textarea>

         <br>

         <input type="text" name="message"  style="width: 300px" value="Welcome to localhost">

         <input type="button" value="发送消息" onclick="send(this.form.message.value)">

         <input type="button" onclick="javascript:document.getElementById('responseText').value=''" value="清空聊天记录">

     </form>

     <br>

         Netty SEO 优化

         Netty 是什么

         Netty 怎么样

         Netty4 Netty5 区别

         Netty 效率

         Netty 版本区别

         Netty 和 Mina

         Netty 网络编程

         Netty Java 网络编程

         Netty Java Socket NIO

         NIO 编程

         Netty NIO 开发

         Netty3 Netty4 Netty5

         Netty 好处

         Netty 一般注意什么

         Netty 例子程序

         Netty Hello World

         Netty 聊天程序

         Netty Web HTML HTTP FTP SSL

         Netty UDP TCP WebSocket 练习

         Netty 连接数

         Netty 源码

     <br>

 </body>

 </html>

　　运行结果，依次运行1，2，3

Netty5 + WebSocket 练习

　　服务器打印结果

Netty5 + WebSocket 练习

参考资料:
　　《Netty 权威指南》
　　https://zh.wikipedia.org/wiki/WebSocket
　　https://www.zhihu.com/question/20215561
　　http://waylau.com/netty-websocket-chat/

本文地址:http://www.cnblogs.com/wunaozai/p/5240006.html

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