一、项目的创建

新建Spring项目：
在这里插入图片描述

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>