Netty

<dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.42.Final</version>
        </dependency>

package com.etc.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
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 InterruptedException {
        // 创建2GE GROUp    bossGroup  wordGroup  线程组
        // 默认 cpu 核数 * 2
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);// 处理连接
        EventLoopGroup wordGroup = new NioEventLoopGroup();// 真正和客户端进行业务处理的。 就交给了wordGroup

        //启动服务端
        ServerBootstrap bootstrap = new ServerBootstrap();

        bootstrap.group(bossGroup, wordGroup)
                .channel(NioServerSocketChannel.class)
                .handler(new LoggingHandler(LogLevel.INFO))
                .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编码器和解码器
                        pipeline.addLast(new HttpServerCodec());
                        // 以快的这种方式进行写入
                        pipeline.addLast(new ChunkedWriteHandler());
                        /**
                         * http 数据在传输过程中是分段的. 就是可以将多个进行聚合
                         * 当浏览器发送大量数据. 就会发送多次http请求
                         */
                        pipeline.addLast(new HttpObjectAggregator(8192));
                        /**
                         * 对应的websocket 他的数据一个帧来发送
                         * 浏览器的请求的地址  ws://localhost:7000/hello  这个是url
                         */
                        pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));



                        pipeline.addLast(new MyTextWebSocketHanlder());

                    }
                });


        ChannelFuture sync = bootstrap.bind(7000).sync();
        sync.addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture future) throws Exception {
                if (future.isSuccess()){
                    System.out.println("websocket服务启动成功端口7000");
                }else {
                    System.out.println("ebsocket服务启动成功失败");
                }
            }
        });
        sync.channel().closeFuture().sync();


    }
}

package com.etc.websocket;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;

import java.time.LocalDateTime;


/**
 * @Author kalista
 * @Description
 * @Date 2020/9/7  14:34
 **/
public class MyTextWebSocketHanlder extends SimpleChannelInboundHandler<TextWebSocketFrame> {


    /**
     * 服务器收到消息
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
        System.out.println("服务器收到消息了:" + msg.text());

        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
     * @param ctx
     * @throws Exception
     */
    @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());


    }


    /**
     * 当连接断开后
     * @param ctx
     * @throws Exception
     */
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        System.out.println("有个连接断开:" + ctx.channel().id().asLongText());
    }

    /**
     * 发送异常
     * @param ctx
     * @param cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("异常:" + cause.getMessage());
        ctx.close();
    }
}