java代码：netty整合websocket实现长连接代码示例

以你之姓@ 2023-09-27 10:26 82阅读 0赞

## 实现效果 ##

![在这里插入图片描述][fbabadee97d14f71873eb1efc3f620d6.png]

## pom ##

<dependency>
        <groupId>io.netty</groupId>
        <artifactId>netty-all</artifactId>
        <version>4.1.68.Final</version>
    </dependency>

## java代码 ##

### MyServer ###

package com.zxl.netty.websocket;
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    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.codec.http.websocketx.WebSocketServerProtocolHandler;
    import io.netty.handler.logging.LogLevel;
    import io.netty.handler.logging.LoggingHandler;
    import io.netty.handler.stream.ChunkedWriteHandler;
    
    public class MyServer {
        
        public static void main(String[] args) throws Exception{
        
    
    
            //创建两个线程组
            EventLoopGroup bossGroup = new NioEventLoopGroup(1);
            EventLoopGroup workerGroup = new NioEventLoopGroup(); //8个NioEventLoop
            try {
        
    
                ServerBootstrap serverBootstrap = new ServerBootstrap();
    
                serverBootstrap.group(bossGroup, workerGroup);
                serverBootstrap.channel(NioServerSocketChannel.class);
                serverBootstrap.handler(new LoggingHandler(LogLevel.INFO));
                serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
        
    
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
        
                        ChannelPipeline pipeline = ch.pipeline();
    
                        //因为基于http协议，使用http的编码和解码器
                        pipeline.addLast(new HttpServerCodec());
                        //是以块方式写，添加ChunkedWriteHandler处理器
                        pipeline.addLast(new ChunkedWriteHandler());
    
                        /*
                        说明
                        1. http数据在传输过程中是分段, HttpObjectAggregator ，就是可以将多个段聚合
                        2. 这就就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                         */
                        pipeline.addLast(new HttpObjectAggregator(8192));
                        /*
                        说明
                        1. 对应websocket ，它的数据是以 帧(frame) 形式传递
                        2. 可以看到WebSocketFrame 下面有六个子类
                        3. 浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                        4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议 , 保持长连接
                        5. 是通过一个 状态码 101
                         */
                        pipeline.addLast(new WebSocketServerProtocolHandler("/hello2"));
    
                        //自定义的handler ，处理业务逻辑
                        pipeline.addLast(new MyTextWebSocketFrameHandler());
                    }
                });
    
                //启动服务器
                ChannelFuture channelFuture = serverBootstrap.bind(7000).sync();
                channelFuture.channel().closeFuture().sync();
    
            }finally {
        
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        }
    }

### MyTextWebSocketFrameHandler ###

package com.zxl.netty.websocket;
    
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.SimpleChannelInboundHandler;
    import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
    
    import java.time.LocalDateTime;
    
    //这里 TextWebSocketFrame 类型，表示一个文本帧(frame)
    public class MyTextWebSocketFrameHandler extends SimpleChannelInboundHandler<TextWebSocketFrame>{
        
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
        
    
            System.out.println("服务器收到消息 " + msg.text());
    
            //回复消息
            ctx.channel().writeAndFlush(new TextWebSocketFrame("服务器时间" + LocalDateTime.now() + " " + msg.text()));
        }
    
        //当web客户端连接后， 触发方法
        @Override
        public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        
            //id 表示唯一的值，LongText 是唯一的 ShortText 不是唯一
            System.out.println("handlerAdded 被调用" + ctx.channel().id().asLongText());
            System.out.println("handlerAdded 被调用" + ctx.channel().id().asShortText());
        }
    
    
        @Override
        public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        
    
            System.out.println("handlerRemoved 被调用" + ctx.channel().id().asLongText());
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        
            System.out.println("异常发生 " + cause.getMessage());
            ctx.close(); //关闭连接
        }
    }

## html ##

### hello.html ###

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <script>
        var socket;
        //判断当前浏览器是否支持websocket
        if(window.WebSocket) {
          
            //go on
            socket = new WebSocket("ws://localhost:7000/hello2");
            //相当于channelReado, ev 收到服务器端回送的消息
            socket.onmessage = function (ev) {
          
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + ev.data;
            }
    
            //相当于连接开启(感知到连接开启)
            socket.onopen = function (ev) {
          
                var rt = document.getElementById("responseText");
                rt.value = "连接开启了.."
            }
    
            //相当于连接关闭(感知到连接关闭)
            socket.onclose = function (ev) {
          
    
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + "连接关闭了.."
            }
        } else {
          
            alert("当前浏览器不支持websocket")
        }
    
        //发送消息到服务器
        function send(message) {
          
            if(!window.socket) {
           //先判断socket是否创建好
                return;
            }
            if(socket.readyState == WebSocket.OPEN) {
          
                //通过socket 发送消息
                socket.send(message)
            } else {
          
                alert("连接没有开启");
            }
        }
    </script>
        <form onsubmit="return false">
            <textarea name="message" style="height: 300px; width: 300px"></textarea>
            <input type="button" value="发送消息" onclick="send(this.form.message.value)">
            <textarea id="responseText" style="height: 300px; width: 300px"></textarea>
            <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''">
        </form>
    </body>
    </html>

[fbabadee97d14f71873eb1efc3f620d6.png]: https://img-blog.csdnimg.cn/fbabadee97d14f71873eb1efc3f620d6.png