websocket+netty实时视频弹幕交互功能（Java版）
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2021年了，还有不支持弹幕的视频网站吗，现在各种弹幕玩法层出不穷，抽奖，ppt都上弹幕玩法了，不整个弹幕都说不过去了，今天笔者就抽空做了一个实时视频弹幕交互功能的实现，不得不说这样的形式为看视频看直播，讲义PPT，抽奖等形式增加了许多乐趣。文章源自JAVA秀-https://www.javaxiu.com/41765.html
1 技术选型
1.1 netty
官方对于netty的描述：文章源自JAVA秀-https://www.javaxiu.com/41765.html
https://netty.io/文章源自JAVA秀-https://www.javaxiu.com/41765.html
主要关键词描述：netty是异步事件驱动网络框架，可做各种协议服务端，并且支持了FTP，SMTP，HTTP等很多协议，并且性能，稳定性，灵活性都很棒。文章源自JAVA秀-https://www.javaxiu.com/41765.html
文章源自JAVA秀-https://www.javaxiu.com/41765.html
可以看到netty整体架构上分了三个部分：文章源自JAVA秀-https://www.javaxiu.com/41765.html
以零拷贝，一致性接口，扩展事件模型的底层核心。文章源自JAVA秀-https://www.javaxiu.com/41765.html
Socket，Datagram，Pipe，Http Tunnel作为传输媒介。文章源自JAVA秀-https://www.javaxiu.com/41765.html
传输支持的各种协议，HTTP&WebSocket，SSL，大文件，zlib/gzip压缩，文本，二进制，Google Protobuf等各种各种的传输形式。文章源自JAVA秀-https://www.javaxiu.com/41765.html
1.2 WebSocket
WebSocket是一种在单个TCP连接上进行全双工通信的协议。WebSocket通信协议于2011年被IETF定为标准RFC 6455，并由RFC7936补充规范。WebSocket API也被W3C定为标准。文章源自JAVA秀-https://www.javaxiu.com/41765.html
WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。文章源自JAVA秀-https://www.javaxiu.com/41765.html
1.3 为什么做这样的技术选型。
由上述可知，实时直播交互作为互动式是一个双向数据传输过程。所以使用webSocket。文章源自JAVA秀-https://www.javaxiu.com/41765.html
netty本身支持了webSocket协议的实现，让实现更加简单方便。文章源自JAVA秀-https://www.javaxiu.com/41765.html
2 实现思路
2.1 服务架构
整体架构是所有客户端都和我的服务端开启一个双向通道的架构。文章源自JAVA秀-https://www.javaxiu.com/41765.html
文章源自JAVA秀-https://www.javaxiu.com/41765.html
2.2 传输流程
文章源自JAVA秀-https://www.javaxiu.com/41765.html
3 实现效果
3.1 视频展示
先看看效果吧，是不是perfect，接下来就来看具体代码是怎么实现的吧。文章源自JAVA秀-https://www.javaxiu.com/41765.html
文章源自JAVA秀-https://www.javaxiu.com/41765.html
视频直播弹幕示例文章源自JAVA秀-https://www.javaxiu.com/41765.html
4 代码实现
4.1 项目结构
一个maven项目，将代码放一个包下就行。文章源自JAVA秀-https://www.javaxiu.com/41765.html
文章源自JAVA秀-https://www.javaxiu.com/41765.html
4.2 Java服务端
Java服务端代码，总共三个类，Server，Initailizer和 Handler。文章源自JAVA秀-https://www.javaxiu.com/41765.html
4.2.1 先做一个netty nio的服务端：
一个nio的服务，开启一个tcp端口。文章源自JAVA秀-https://www.javaxiu.com/41765.html
import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.nio.NioServerSocketChannel;/** * Copyright(c)lbhbinhao@163.com * @author liubinhao * @date 2021/1/14 * ++++ ______ ______ ______ * +++/ /| / /| / /| * +/_____/ | /_____/ | /_____/ | * | | | | | | | | | * | | | | | |________| | | * | | | | | / | | | * | | | | |/___________| | | * | | |___________________ | |____________| | | * | | / / | | | | | | | * | |/ _________________/ / | | / | | / * |_________________________|/b |_____|/ |_____|/ */public enum BulletChatServer { /** * Server instance */ SERVER; private BulletChatServer(){ EventLoopGroup mainGroup = new NioEventLoopGroup(); EventLoopGroup subGroup = new NioEventLoopGroup(); ServerBootstrap server = new ServerBootstrap(); server.group(mainGroup,subGroup) .channel(NioServerSocketChannel.class) .childHandler(new BulletChatInitializer()); ChannelFuture future = server.bind(9123); } public static void main(String[] args) { }}4.2.2 服务端的具体处理逻辑
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;import io.netty.handler.timeout.IdleStateHandler;/** * Copyright(c)lbhbinhao@163.com * * @author liubinhao * @date 2021/1/14 * ++++ ______ ______ ______ * +++/ /| / /| / /| * +/_____/ | /_____/ | /_____/ | * | | | | | | | | | * | | | | | |________| | | * | | | | | / | | | * | | | | |/___________| | | * | | |___________________ | |____________| | | * | | / / | | | | | | | * | |/ _________________/ / | | / | | / * |_________________________|/b |_____|/ |_____|/ */public class BulletChatInitializer extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast(new HttpServerCodec()); pipeline.addLast(new ChunkedWriteHandler()); pipeline.addLast(new HttpObjectAggregator(1024*64)); pipeline.addLast(new IdleStateHandler(8, 10, 12)); pipeline.addLast(new WebSocketServerProtocolHandler("/lbh")); pipeline.addLast(new BulletChatHandler()); }}后台处理逻辑，接受到消息，写出到所有的客户端：文章源自JAVA秀-https://www.javaxiu.com/41765.html
import io.netty.channel.Channel;import io.netty.channel.ChannelHandler;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;import io.netty.channel.group.ChannelGroup;import io.netty.channel.group.DefaultChannelGroup;import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;import io.netty.util.concurrent.EventExecutorGroup;import io.netty.util.concurrent.GlobalEventExecutor;/** * Copyright(c)lbhbinhao@163.com * * @author liubinhao * @date 2021/1/14 * ++++ ______ ______ ______ * +++/ /| / /| / /| * +/_____/ | /_____/ | /_____/ | * | | | | | | | | | * | | | | | |________| | | * | | | | | / | | | * | | | | |/___________| | | * | | |___________________ | |____________| | | * | | / / | | | | | | | * | |/ _________________/ / | | / | | / * |_________________________|/b |_____|/ |_____|/ */public class BulletChatHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> { // 用于记录和管理所有客户端的channel public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); @Override protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception { // 获取客户端传输过来的消息 String content = msg.text(); System.err.println("收到消息："+ content); channels.writeAndFlush(new TextWebSocketFrame(content)); System.err.println("写出消息完成："+content); } @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { channels.add(ctx.channel()); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { String channelId = ctx.channel().id().asShortText(); System.out.println("客户端被移除，channelId为：" + channelId); channels.remove(ctx.channel()); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); // 发生异常之后关闭连接（关闭channel），随后从ChannelGroup中移除 ctx.channel().close(); channels.remove(ctx.channel()); }}4.3 网页客户端实现
<!DOCTYPE html><html lang="en"><head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <title>Netty视频弹幕实现 Author:Binhao Liu</title> <link rel="stylesheet" href=""> <style type="text/css" media="screen"> * { margin: 0px; padding: 0px } html, body { height: 100% } body { overflow: hidden; background-color: #FFF; text-align: center; } .flex-column { display: flex; flex-direction: column; justify-content: space-between;, align-items: center; } .flex-row { display: flex; flex-direction: row; justify-content: center; align-items: center; } .wrap { overflow: hidden; width: 70%; height: 600px; margin: 100px auto; padding: 20px; background-color: transparent; box-shadow: 0 0 9px #222; border-radius: 20px; } .wrap .box { position: relative; width: 100%; height: 90%; background-color: #000000; border-radius: 10px } .wrap .box span { position: absolute; top: 10px; left: 20px; display: block; padding: 10px; color: #336688 } .wrap .send { display: flex; width: 100%; height: 10%; background-color: #000000; border-radius: 8px } .wrap .send input { width: 40%; height: 60%; border: 0; outline: 0; border-radius: 5px 0px 0px 5px; box-shadow: 0px 0px 5px #d9d9d9; text-indent: 1em } .wrap .send .send-btn { width: 100px; height: 60%; background-color: #fe943b; color: #FFF; text-align: center; border-radius: 0px 5px 5px 0px; line-height: 30px; cursor: pointer; } .wrap .send .send-btn:hover { background-color: #4cacdc } </style></head><script> var ws = new WebSocket("ws://localhost:9123/lbh"); ws.onopen = function () { // Web Socket 已连接上，使用 send() 方法发送数据 alert("数据发送中..."); }; ws.onmessage = function (e) { console.log("接受到消息:"+e.data); createEle(e.data); }; ws.onclose = function () { // 关闭 websocket alert("连接已关闭..."); }; function sendMsg(msg) { ws.send(msg) }</script><body><div class="wrap flex-column"> <div class="box"> <video src="shape.mp4" width="100%" height="100%" controls autoplay></video> </div> <div class="send flex-row"> <input type="text" class="con" placeholder="弹幕发送[]~(^v^)~*"/> <div class="send-btn" onclick="javascript:sendMsg(document.querySelector('.con').value)">发送</div> </div></div><script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js" type="text/javascript"></script><script> //1.获取元素 var oBox = document.querySelector('.box'); //获取.box元素 var cW = oBox.offsetWidth; //获取box的宽度 var cH = oBox.offsetHeight; //获取box的高度 function createEle(txt) { //动态生成span标签 var oMessage = document.createElement('span'); //创建标签 oMessage.innerHTML = txt; //接收参数txt并且生成替换内容 oMessage.style.left = cW + 'px'; //初始化生成位置x oBox.appendChild(oMessage); //把标签塞到oBox里面 roll.call(oMessage, { //call改变函数内部this的指向 timing: ['linear', 'ease-out'][~~(Math.random() * 2)], color: '#' + (~~(Math.random() * (1 << 24))).toString(16), top: random(0, cH), fontSize: random(16, 32) }); } function roll(opt) { //弹幕滚动 //如果对象中不存在timing 初始化 opt.timing = opt.timing || 'linear'; opt.color = opt.color || '#fff'; opt.top = opt.top || 0; opt.fontSize = opt.fontSize || 16; this._left = parseInt(this.offsetLeft); //获取当前left的值 this.style.color = opt.color; //初始化颜色 this.style.top = opt.top + 'px'; this.style.fontSize = opt.fontSize + 'px'; this.timer = setInterval(function () { if (this._left <= 100) { clearInterval(this.timer); //终止定时器 this.parentNode.removeChild(this); return; //终止函数 } switch (opt.timing) { case 'linear': //如果匀速 this._left += -2; break; case 'ease-out': // this._left += (0 - this._left) * .01; break; } this.style.left = this._left + 'px'; }.bind(this), 1000 / 60); } function random(start, end) { //随机数封装 return start + ~~(Math.random() * (end - start)); } var aLi = document.querySelectorAll('li'); //10 function forEach(ele, cb) { for (var i = 0, len = aLi.length; i < len; i++) { cb && cb(ele[i], i); } } forEach(aLi, function (ele, i) { ele.style.left = i * 100 + 'px'; }); //产生闭包 var obj = { num: 1, add: function () { this.num++; //obj.num = 2; (function () { console.log(this.num); }) } }; obj.add();//window</script></body></html>这样一个实时的视频弹幕功能就完成啦，是不是很简单，各位小伙伴快来试试吧。文章源自JAVA秀-https://www.javaxiu.com/41765.html
5 小结
上班撸代码，下班继续撸代码写博客，这个还是很简单，笔者写这个的时候一会儿就写完了，不过这也得益于笔者很久以前就写过netty的服务，对于Http，Tcp之类协议也比较熟悉，只有前端会有些难度，问下度娘，也很快能做完，在此分享出来与诸君分享，有问题可找笔者交流。文章源自JAVA秀-https://www.javaxiu.com/41765.html
欢迎一键三连，拒绝做伸手党！文章源自JAVA秀-https://www.javaxiu.com/41765.html
（感谢阅读，希望对你所有帮助)文章源自JAVA秀-https://www.javaxiu.com/41765.html
来源：binhao.blog.csdn.net/article/details/112631642文章源自JAVA秀-https://www.javaxiu.com/41765.html
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