大家好，又见面了，我是你们的朋友全栈君。

一、项目的创建

新建Spring项目：

选择JDK版本：

选择Spring Web：

项目名称和位置的设置：

二、代码编写

导入.jar包：

gson: https://search.maven.org/artifact/com.google.code.gson/gson/2.8.9/jar

DemoApplication:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.env.Environment;

import java.net.InetAddress;
import java.net.UnknownHostException;

@SpringBootApplication
public class DemoApplication { 
   

    public static void main(String[] args) throws UnknownHostException { 
   
        ConfigurableApplicationContext application = SpringApplication.run(DemoApplication.class, args);
        Environment env = application.getEnvironment();
        String host = InetAddress.getLocalHost().getHostAddress();
        String port = env.getProperty("server.port");
        System.out.println("[----------------------------------------------------------]");
        System.out.println("聊天室启动成功！点击进入:\t http://" + host + ":" + port);
        System.out.println("[----------------------------------------------------------");
        WebSocketServer.inst().run(53134);
    }

}

User:

package com.example.demo;

import java.util.Objects;

public class User { 
   

    public String id;
    public String nickname;

    public User(String id, String nickname) { 
   
        super();
        this.id = id;
        this.nickname = nickname;
    }

    public String getId() { 
   
        return id;
    }

    public void setId(String id) { 
   
        this.id = id;
    }

    public String getNickname() { 
   
        return nickname;
    }

    public void setNickname(String nickname) { 
   
        this.nickname = nickname;
    }

    @Override
    public boolean equals(Object o) { 
   
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;
        User user = (User) o;
        return id.equals(user.getId());
    }

    @Override
    public int hashCode() { 
   

        return Objects.hash(id);
    }

    public String getUid() { 
   

        return id;
    }
}

SessionGroup:

package com.example.demo;

import com.google.gson.Gson;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.ChannelGroupFuture;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.util.concurrent.ImmediateEventExecutor;
import org.springframework.util.StringUtils;

import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public final class SessionGroup { 
   

    private static SessionGroup singleInstance = new SessionGroup();

    // 组的映射
    private ConcurrentHashMap<String, ChannelGroup> groupMap = new ConcurrentHashMap<>();

    public static SessionGroup inst() { 
   
        return singleInstance;
    }

    public void shutdownGracefully() { 
   

        Iterator<ChannelGroup> groupIterator = groupMap.values().iterator();
        while (groupIterator.hasNext()) { 
   
            ChannelGroup group = groupIterator.next();
            group.close();
        }
    }

    public void sendToOthers(Map<String, String> result, SocketSession s) { 
   
        // 获取组
        ChannelGroup group = groupMap.get(s.getGroup());
        if (null == group) { 
   
            return;
        }
        Gson gson=new Gson();
        String json = gson.toJson(result);
        // 自己发送的消息不返回给自己
// Channel channel = s.getChannel();
        // 从组中移除通道
// group.remove(channel);
        ChannelGroupFuture future = group.writeAndFlush(new TextWebSocketFrame(json));
        future.addListener(f -> { 
   
            System.out.println("完成发送："+json);
// group.add(channel);//发送消息完毕重新添加。

        });
    }

    public void addSession(SocketSession session) { 
   

        String groupName = session.getGroup();
        if (StringUtils.isEmpty(groupName)) { 
   
            // 组为空，直接返回
            return;
        }
        ChannelGroup group = groupMap.get(groupName);
        if (null == group) { 
   
            group = new DefaultChannelGroup(ImmediateEventExecutor.INSTANCE);
            groupMap.put(groupName, group);
        }
        group.add(session.getChannel());
    }

    /** * 关闭连接， 关闭前发送一条通知消息 */
    public void closeSession(SocketSession session, String echo) { 
   
        ChannelFuture sendFuture = session.getChannel().writeAndFlush(new TextWebSocketFrame(echo));
        sendFuture.addListener(new ChannelFutureListener() { 
   
            public void operationComplete(ChannelFuture future) { 
   
                System.out.println("关闭连接："+echo);
                future.channel().close();
            }
        });
    }

    /** * 关闭连接 */
    public void closeSession(SocketSession session) { 
   

        ChannelFuture sendFuture = session.getChannel().close();
        sendFuture.addListener(new ChannelFutureListener() { 
   
            public void operationComplete(ChannelFuture future) { 
   
                System.out.println("发送所有完成："+session.getUser().getNickname());
            }
        });

    }

    /** * 发送消息 * @param ctx 上下文 * @param msg 待发送的消息 */
    public void sendMsg(ChannelHandlerContext ctx, String msg) { 
   
        ChannelFuture sendFuture = ctx.writeAndFlush(new TextWebSocketFrame(msg));
        sendFuture.addListener(f -> { 
   //发送监听
            System.out.println("对所有发送完成："+msg);
        });
    }
}

SocketSession:

package com.example.demo;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.AttributeKey;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

public class SocketSession { 
   

    public static final AttributeKey<SocketSession> SESSION_KEY = AttributeKey.valueOf("SESSION_KEY");

    /** * 用户实现服务端会话管理的核心 */
// 通道
    private Channel channel;
    // 用户
    private User user;

    // session唯一标示
    private final String sessionId;

    private String group;

    /** * session中存储的session 变量属性值 */
    private Map<String, Object> map = new HashMap<String, Object>();

    public SocketSession(Channel channel) { 
   //注意传入参数channel。不同客户端会有不同channel
        this.channel = channel;
        this.sessionId = buildNewSessionId();
        channel.attr(SocketSession.SESSION_KEY).set(this);
    }

    // 反向导航
    public static SocketSession getSession(ChannelHandlerContext ctx) { 
   //注意ctx，不同的客户端会有不同ctx
        Channel channel = ctx.channel();
        return channel.attr(SocketSession.SESSION_KEY).get();
    }

    // 反向导航
    public static SocketSession getSession(Channel channel) { 
   
        return channel.attr(SocketSession.SESSION_KEY).get();
    }

    public String getId() { 
   
        return sessionId;
    }

    private static String buildNewSessionId() { 
   
        String uuid = UUID.randomUUID().toString();
        return uuid.replaceAll("-", "");
    }

    public synchronized void set(String key, Object value) { 
   
        map.put(key, value);
    }

    public synchronized <T> T get(String key) { 
   
        return (T) map.get(key);
    }

    public boolean isValid() { 
   
        return getUser() != null ? true : false;
    }

    public User getUser() { 
   
        return user;
    }

    public void setUser(User user) { 
   
        this.user = user;
    }

    public String getGroup() { 
   
        return group;
    }

    public void setGroup(String group) { 
   
        this.group = group;
    }

    public Channel getChannel() { 
   
        return channel;
    }
}

WebSocketServer:

package com.example.demo;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
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.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.handler.timeout.IdleStateHandler;

import java.util.concurrent.TimeUnit;

public class WebSocketServer { 
   

    private static WebSocketServer wbss;

    private static final int READ_IDLE_TIME_OUT = 60; // 读超时
    private static final int WRITE_IDLE_TIME_OUT = 0;// 写超时
    private static final int ALL_IDLE_TIME_OUT = 0; // 所有超时

    public static WebSocketServer inst() { 
   
        return wbss = new WebSocketServer();
    }

    public void run(int port) { 
   
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer <SocketChannel>() { 
   
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception { 
   
                        ChannelPipeline pipeline = ch.pipeline();
                        // Netty自己的http解码器和编码器，报文级别 HTTP请求的解码和编码
                        pipeline.addLast(new HttpServerCodec());
                        // ChunkedWriteHandler 是用于大数据的分区传输
                        // 主要用于处理大数据流，比如一个1G大小的文件如果你直接传输肯定会撑暴jvm内存的;
                        // 增加之后就不用考虑这个问题了
                        pipeline.addLast(new ChunkedWriteHandler());
                        // HttpObjectAggregator 是完全的解析Http消息体请求用的
                        // 把多个消息转换为一个单一的完全FullHttpRequest或是FullHttpResponse，
                        // 原因是HTTP解码器会在每个HTTP消息中生成多个消息对象HttpRequest/HttpResponse,HttpContent,LastHttpContent
                        pipeline.addLast(new HttpObjectAggregator(64 * 1024));
                        // WebSocket数据压缩
                        pipeline.addLast(new WebSocketServerCompressionHandler());
                        // WebSocketServerProtocolHandler是配置websocket的监听地址/协议包长度限制
                        pipeline.addLast(new WebSocketServerProtocolHandler("/ws", null, true, 10 * 1024));

                        // 当连接在60秒内没有接收到消息时，就会触发一个 IdleStateEvent 事件，
                        // 此事件被 HeartbeatHandler 的 userEventTriggered 方法处理到
                        pipeline.addLast(
                                new IdleStateHandler(READ_IDLE_TIME_OUT, WRITE_IDLE_TIME_OUT, ALL_IDLE_TIME_OUT, TimeUnit.SECONDS));

                        // WebSocketServerHandler、TextWebSocketFrameHandler 是自定义逻辑处理器，
                        pipeline.addLast(new WebSocketTextHandler());
                    }
                });
        Channel ch = b.bind(port).syncUninterruptibly().channel();
        ch.closeFuture().syncUninterruptibly();

        // 返回与当前Java应用程序关联的运行时对象
        Runtime.getRuntime().addShutdownHook(new Thread() { 
   
            @Override
            public void run() { 
   
                SessionGroup.inst().shutdownGracefully();
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        });
    }
}

WebSocketTextHandler:

package com.example.demo;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;

import java.util.HashMap;
import java.util.Map;


public class WebSocketTextHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> { 
   

    //@Override
    protected void channelRead(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception { 
   
        SocketSession session = SocketSession.getSession(ctx);
        TypeToken<HashMap<String, String>> typeToken = new TypeToken<HashMap<String, String>>() { 
   
        };

        Gson gson=new Gson();
        java.util.Map<String,String> map = gson.fromJson(msg.text(), typeToken.getType());
        User user = null;
        switch (map.get("type")) { 
   
            case "msg":
                Map<String, String> result = new HashMap<>();
                user = session.getUser();
                result.put("type", "msg");
                result.put("msg", map.get("msg"));
                result.put("sendUser", user.getNickname());
                SessionGroup.inst().sendToOthers(result, session);
                break;
            case "init":
                String room = map.get("room");
                session.setGroup(room);
                String nick = map.get("nick");
                user = new User(session.getId(), nick);
                session.setUser(user);
                SessionGroup.inst().addSession(session);
                break;
        }
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception { 
   

        // 是否握手成功，升级为 Websocket 协议
        if (evt == WebSocketServerProtocolHandler.ServerHandshakeStateEvent.HANDSHAKE_COMPLETE) { 
   
            // 握手成功，移除 HttpRequestHandler，因此将不会接收到任何消息
            // 并把握手成功的 Channel 加入到 ChannelGroup 中
            new SocketSession(ctx.channel());
        } else if (evt instanceof IdleStateEvent) { 
   
            IdleStateEvent stateEvent = (IdleStateEvent) evt;
            if (stateEvent.state() == IdleState.READER_IDLE) { 
   
                System.out.println("bb22");
            }
        } else { 
   
            super.userEventTriggered(ctx, evt);
        }
    }


    @Override
    protected void messageReceived(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception { 
   

    }
}

之后项目外创建一个test.html:

<!DOCTYPE HTML>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title>群聊天室</title>     
    <style type="text/css"> body { 
      margin-right:50px; margin-left:50px; } .ddois { 
      position: fixed; left: 120px; bottom: 30px; } </style>        
</head>
<body>
     群名：<input type="text" id="room" name="group" placeholder="请输入群">
    <br /><br />
     昵称：<input type="text" id="nick" name="name" placeholder="请输入昵称">
    <br /><br />
    <button type="button" onclick="enter()">进入聊天群</button>
    <br /><br />        
    <div id="message"></div>
    <br /><br />        
    <div class="ddois">
    <textarea name="send" id="text" rows="10" cols="30" placeholder="输入发送消息"></textarea>
    <br /><br />
    <button type="button" onclick="send()">发送</button>
    </div>      
    <script type="text/javascript"> var webSocket; if (window.WebSocket) { 
      webSocket = new WebSocket("ws://localhost:53134/ws"); } else { 
      alert("抱歉，您的浏览器不支持WebSocket协议!"); } //连通之后的回调事件 webSocket.onopen = function() { 
      console.log("已经连通了websocket"); // setMessageInnerHTML("已经连通了websocket"); }; //连接发生错误的回调方法 webSocket.onerror = function(event){ 
      console.log("出错了"); // setMessageInnerHTML("连接失败"); }; //连接关闭的回调方法 webSocket.onclose = function(){ 
      console.log("连接已关闭..."); } //接收到消息的回调方法 webSocket.onmessage = function(event){ 
      console.log("bbdds"); var data = JSON.parse(event.data) var msg = data.msg; var nick = data.sendUser; switch(data.type){ 
      case 'init': console.log("mmll"); break; case 'msg': console.log("bblld"); setMessageInnerHTML(nick+": "+msg); break; default: break; } } function enter(){ 
      var map = new Map(); var nick=document.getElementById('nick').value; var room=document.getElementById('room').value; map.set("type","init"); map.set("nick",nick); console.log(room); map.set("room",room); var message = Map2Json(map); webSocket.send(message); } function send() { 
      var msg = document.getElementById('text').value; var nick = document.getElementById('nick').value; console.log("1:"+msg); if (msg != null && msg != ""){ 
      var map = new Map(); map.set("type","msg"); map.set("msg",msg); var map2json=Map2Json(map); if (map2json.length < 8000){ 
      console.log("4:"+map2json); webSocket.send(map2json); }else { 
      console.log("文本太长了，少写一点吧?"); } } } //将消息显示在网页上 function setMessageInnerHTML(innerHTML) { 
      document.getElementById("message").innerHTML += innerHTML + "<br/>"; } function Map2Json(map) { 
      var str = "{"; map.forEach(function (value, key) { 
      str += '"'+key+'"'+':'+ '"'+value+'",'; }) str = str.substring(0,str.length-1) str +="}"; return str; } </script>

</body> 
</html>

先运行项目，然后运行html：

参考

springboot和netty整合的聊天室–群聊

springboot+netty实现网络聊天