1.搭建netty服务器

1.创建maven项目

使用netty和natapp搭建公网多人在线聊天demo

2.引入依赖

		<dependency>
			<groupId>io.netty</groupId>
			<artifactId>netty-all</artifactId>
			<version>4.1.25.Final</version>
		</dependency>

3.创建netty的main方法

package com.cxl.websco;

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;

public class WSServer {
	
	public static void main(String[] args) throws InterruptedException {
		
		EventLoopGroup mainGroup = new NioEventLoopGroup();
		EventLoopGroup subGroup = new NioEventLoopGroup();
		try {
			ServerBootstrap serverBootstrap = new ServerBootstrap();
			serverBootstrap.group(mainGroup,subGroup)
			.channel(NioServerSocketChannel.class)
			.childHandler(new WSServerInitialzer());
			
			ChannelFuture channelFuture = serverBootstrap.bind(8083).sync();
			channelFuture.channel().closeFuture().sync();
		} finally {
			mainGroup.shutdownGracefully();
			mainGroup.shutdownGracefully();
		}
	}
}

4.创建初始化容器

package com.cxl.websco;

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;

public class WSServerInitialzer extends ChannelInitializer<SocketChannel>{

	@Override
	protected void initChannel(SocketChannel channel) throws Exception {
		ChannelPipeline pipeline = channel.pipeline();
		
		//编解码器
		pipeline.addLast(new HttpServerCodec());
		//对大数据流处理
		pipeline.addLast(new ChunkedWriteHandler());
		// 对httpmessage进行聚合，聚合成fullhttprequest或fullhttpresponse
		// 几乎在netty中的编程都会使用到此hanler
		pipeline.addLast(new HttpObjectAggregator(1024*64));
		
		//===================以上是用于支持http协议===================
		
		//websocket服务器处理的协议，用于指定给客户端连接访问的路由
		pipeline.addLast(
				new WebSocketServerProtocolHandler("/ws"));
		
		//自定义拦截器
		pipeline.addLast(new ChatHandler());
			
	}
}

5.创建自定义拦截器

package com.cxl.websco;

import java.time.LocalDateTime;

import io.netty.channel.Channel;
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.channel.local.LocalChannel;
import io.netty.handler.codec.http.HttpObject;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.util.concurrent.GlobalEventExecutor;

/**
 *  处理消息的handler
 * @author mingliang
 *TextWebSocketFrame websocket专门处理文本的对象 ，frame是载体
 */
public class ChatHandler extends SimpleChannelInboundHandler<TextWebSocketFrame>{

	//管理所有客户端的channel
	private static ChannelGroup clients = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

	
	@Override
	protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
		String content = msg.text(); // 获取客户端传过来的消息内容
		System.out.println("msg : "+content);
		
		for (Channel channel : clients) {
			channel.writeAndFlush(
					new TextWebSocketFrame
					("[服务器在：]"+LocalDateTime.now()+
							",接收到消息为："+content));
		}
		
		//以下写法和for循环一致
//		clients.writeAndFlush(new TextWebSocketFrame
//					("[服务器在：]"+LocalDateTime.now()+
//							",接收到消息为："+content));
	}
	
	//用户进入
	@Override
	public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
		clients.add(ctx.channel());
		System.out.println("添加cid" + ctx.channel().id());clients.add(ctx.channel());
	}

	//用户离开
	@Override
	public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
		clients.remove(ctx.channel());
		System.out.println("移除cid" + ctx.channel().id());
		System.out.println("移除长id" + ctx.channel().id().asLongText());
		System.out.println("移除短id" + ctx.channel().id().asShortText());
	}
	
	

}

2.编写前端页面

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		
		
		<div>发送消息：</div>
		<input type="text" id="msgContent" />
		<input type="button" value="点我发送" onclick="CHAT.chat()" />
		
		<div>接收消息：</div>
		<div id="receiveMsg" style="background-color: gainsboro;"></div>
		
		<script type="application/javascript">
			
			window.CHAT={
				socket:null,
				init:function(){
					if(window.WebSocket){
						CHAT.socket = new WebSocket("ws://pf4g8f.natappfree.cc/ws");
						CHAT.socket.onopen = function(){
							console.log("连接建立成功")
						},
						CHAT.socket.onmessage = function(e){
							console.log("接收到消息："+e.data)
							var msg = document.getElementById("receiveMsg")
							var html = msg.innerHTML;
							msg.innerHTML = html +"<br/>"+ e.data;
						},
						CHAT.socket.onclose = function(){
							console.log("连接关闭")
						},
						CHAT.socket.onerror = function(){
							console.log("发生错误")
						}
					}else{
						alert("浏览器不支持WebSocket")
					}
				},
				chat:function(){
					var msg = document.getElementById("msgContent");
					CHAT.socket.send(msg.value);
				},	
			}
			
			
			CHAT.init();
				
		</script>
		
	</body>
</html>

3.搭建natapp服务器

官方网站：https://natapp.cn/
注册账号-登录-这里需要两个域名！
一个是netty服务器的公网域名，一个是公网域名
使用netty和natapp搭建公网多人在线聊天demo

这边我购买了一个VIP1的，一个月也就几块钱

1.搭建nginx

去官网下载个nginx-win版
修改conf文件

#user  nobody;
worker_processes  1;


#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;

    keepalive_timeout  65;

    server {
        listen       7777;
        server_name  localhost;
			root D:/HBuilderProjects/WebChat/;

    

        location / {
            index  index.html index.htm;
        }

       
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}