Spring Boot + Netty + WebSocket 实现消息推送

Posted 2023-03-19 WK_BlogYard

springboot和netty，websocket实现消息主动推送

注：本文转自：https://mp.weixin.qq.com/s/YWjGdz-4PzOCDfEt4GPoew

1.关于Netty

Netty 是一个利用 Java 的高级网络的能力，隐藏其背后的复杂性而提供一个易于使用的 API 的客户端/服务器框架。

2.Maven依赖

<dependencies>
 <!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
 <dependency>
  <groupId>io.netty</groupId>
  <artifactId>netty-all</artifactId>
  <version>4.1.36.Final</version>
 </dependency>
</dependencies>

3.SpringBootApplication

启动器中需要new一个NettyServer，并显式调用启动netty。

@SpringBootApplication
public class SpringCloudStudyDemoApplication 
 public static void main(String[] args) 
  SpringApplication.run(SpringCloudStudyDemoApplication.class,args);
  try 
   new NettyServer(12345).start();
   System.out.println("https://blog.csdn.net/moshowgame");
   System.out.println("http://127.0.0.1:6688/netty-websocket/index");
  catch(Exception e) 
   System.out.println("NettyServerError:"+e.getMessage());
  
 

4.NettyServer

启动的NettyServer，这里进行配置

 

/**
 * NettyServer Netty服务器配置
 */
public class NettyServer 

    private final int port;

    public NettyServer(int port) 
        this.port = port;
    

    public void start() throws Exception 
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup group = new NioEventLoopGroup();

        try 
            ServerBootstrap sb = new ServerBootstrap();
            sb.option(ChannelOption.SO_BACKLOG, 1024);
            sb.group(group, bossGroup) // 绑定线程池
                    .channel(NioServerSocketChannel.class) // 指定使用的channel
                    .localAddress(this.port)// 绑定监听端口
                    .childHandler(new ChannelInitializer<SocketChannel>()  // 绑定客户端连接时候触发操作
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception 
                            System.out.println("收到新连接");

                            //websocket协议本身是基于http协议的，所以这边也要使用http解编码器
                            ch.pipeline().addLast(new HttpServerCodec());

                            //以块的方式来写的处理器
                            ch.pipeline().addLast(new ChunkedWriteHandler());
                            ch.pipeline().addLast(new HttpObjectAggregator(8192));
                            ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", null, true, 65536 * 10));
                            ch.pipeline().addLast(new MyWebSocketHandler());
                        
                    );

            ChannelFuture cf = sb.bind().sync(); // 服务器异步创建绑定
            System.out.println(NettyServer.class + " 启动正在监听：" + cf.channel().localAddress());
            cf.channel().closeFuture().sync(); // 关闭服务器通道
         finally 
            group.shutdownGracefully().sync(); // 释放线程池资源
            bossGroup.shutdownGracefully().sync();
        
    

5.MyChannelHandlerPool

通道组池，管理所有websocket连接

/**
 * MyChannelHandlerPool
 * 通道组池，管理所有websocket连接
 */
public class MyChannelHandlerPool 

    public MyChannelHandlerPool()

    public static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

6.MyWebSocketHandler

处理ws一下几种情况：

• channelActive与客户端建立连接
• channelInactive与客户端断开连接
• channelRead0客户端发送消息处理

/**
 * NettyServer Netty服务器配置
 */
public class NettyServer 

    private final int port;

    public NettyServer(int port) 
        this.port = port;
    

    public void start() throws Exception 
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup group = new NioEventLoopGroup();
        try 
            ServerBootstrap sb = new ServerBootstrap();
            sb.option(ChannelOption.SO_BACKLOG, 1024);
            sb.group(group, bossGroup) // 绑定线程池
                    .channel(NioServerSocketChannel.class) // 指定使用的channel
                    .localAddress(this.port)// 绑定监听端口
                    .childHandler(new ChannelInitializer<SocketChannel>()  // 绑定客户端连接时候触发操作

                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception 
                            System.out.println("收到新连接");
                            //websocket协议本身是基于http协议的，所以这边也要使用http解编码器
                            ch.pipeline().addLast(new HttpServerCodec());
                            //以块的方式来写的处理器
                            ch.pipeline().addLast(new ChunkedWriteHandler());
                            ch.pipeline().addLast(new HttpObjectAggregator(8192));
                            ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", "WebSocket", true, 65536 * 10));
                            ch.pipeline().addLast(new MyWebSocketHandler());
                        
                    );

            ChannelFuture cf = sb.bind().sync(); // 服务器异步创建绑定
            System.out.println(NettyServer.class + " 启动正在监听：" + cf.channel().localAddress());
            cf.channel().closeFuture().sync(); // 关闭服务器通道
         finally 
            group.shutdownGracefully().sync(); // 释放线程池资源
            bossGroup.shutdownGracefully().sync();
        
    

7.socket.html

主要是连接ws，发送消息，以及消息反馈

 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Netty-Websocket</title>
    <script type="text/javascript">
        // by zhengkai.blog.csdn.net
        var socket;
        if(!window.WebSocket)
            window.WebSocket = window.MozWebSocket;
        

        if(window.WebSocket)
            socket = new WebSocket("ws://127.0.0.1:12345/ws");
            socket.onmessage = function(event)
                var ta = document.getElementById(\'responseText\');
                ta.value += event.data+"\\r\\n";
            ;
            socket.onopen = function(event)
                var ta = document.getElementById(\'responseText\');
                ta.value = "Netty-WebSocket服务器。。。。。。连接 \\r\\n";
            ;
            socket.onclose = function(event)
                var ta = document.getElementById(\'responseText\');
                ta.value = "Netty-WebSocket服务器。。。。。。关闭 \\r\\n";
            ;
        else
            alert("您的浏览器不支持WebSocket协议！");
        

        function send(message)
            if(!window.WebSocket)return;
            if(socket.readyState == WebSocket.OPEN)
                socket.send(message);
            else
                alert("WebSocket 连接没有建立成功！");
            
        
    </script>
</head>
<body>
<form onSubmit="return false;">
    <label>ID</label><input type="text" name="uid" value="$uid!!" /> <br />
    <label>TEXT</label><input type="text" name="message" value="这里输入消息" /> <br />
    <br /> <input type="button" value="发送ws消息"
                  onClick="send(this.form.uid.value+\':\'+this.form.message.value)" />
    <hr color="black" />
    <h3>服务端返回的应答消息</h3>
    <textarea id="responseText" style="width: 1024px;height: 300px;"></textarea>
</form>
</body>
</html>

8.Controller

写好了html当然还需要一个controller来引导页面。

@RestController
public class IndexController 

 @GetMapping("/index")
 public ModelAndView index()
  ModelAndView mav=new ModelAndView("socket");
  mav.addObject("uid", RandomUtil.randomNumbers(6));
  return mav;
 

9.效果演示

 

 

 

 

 

 10.改造netty支持url参数

1.首先，调整一下加载handler的顺序，优先MyWebSocketHandler在WebSocketServerProtocolHandler之上。

ch.pipeline().addLast(new MyWebSocketHandler());
ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", null, true, 65536 * 10));

2.其次，改造MyWebSocketHandler 的channelRead方法，首次连接会是一个FullHttpRequest类型，可以通过FullHttpRequest.uri()获取完整ws的URL地址，之后接受信息的话，会是一个TextWebSocketFrame类型。

public class MyWebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> 

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception 
        System.out.println("与客户端建立连接，通道开启！");

        //添加到channelGroup通道组
        MyChannelHandlerPool.channelGroup.add(ctx.channel());
    

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception 
        System.out.println("与客户端断开连接，通道关闭！");

        //添加到channelGroup 通道组
        MyChannelHandlerPool.channelGroup.remove(ctx.channel());
    

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception 
        //首次连接是FullHttpRequest，处理参数 by zhengkai.blog.csdn.net
        if (null != msg && msg instanceof FullHttpRequest) 
            FullHttpRequest request = (FullHttpRequest) msg;
            String uri = request.uri();
            Map paramMap=getUrlParams(uri);
            System.out.println("接收到的参数是："+JSON.toJSONString(paramMap));
            //如果url包含参数，需要处理
            if(uri.contains("?"))
                String newUri=uri.substring(0,uri.indexOf("?"));
                System.out.println(newUri);
                request.setUri(newUri);
            
        else if(msg instanceof TextWebSocketFrame)
            //正常的TEXT消息类型
            TextWebSocketFrame frame=(TextWebSocketFrame)msg;
            System.out.println("客户端收到服务器数据：" +frame.text());
            sendAllMessage(frame.text());
        
        super.channelRead(ctx, msg);
    

    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception 

    

    private void sendAllMessage(String message)
        //收到信息后，群发给所有channel
        MyChannelHandlerPool.channelGroup.writeAndFlush( new TextWebSocketFrame(message));
    

    private static Map getUrlParams(String url)
        Map<String,String> map = new HashMap<>();
        url = url.replace("?",";");
        if (!url.contains(";"))
            return map;
        

        if (url.split(";").length > 0)
            String[] arr = url.split(";")[1].split("&");
            for (String s : arr)
                String key = s.split("=")[0];
                String value = s.split("=")[1];
                map.put(key,value);
            
            return  map;
        else
            return map;
        
    

3.html中的ws地址也进行改造

socket = new WebSocket("ws://127.0.0.1:12345/ws?uid=666&gid=777");

4.改造后控制台输出情况

收到新连接
与客户端建立连接，通道开启！
接收到的参数是："uid":"666","gid":"777"
/ws
客户端收到服务器数据：142531:这里输入消息
客户端收到服务器数据：142531:这里输入消息
客户端收到服务器数据：142531:这里输入消息

failed: WebSocket opening handshake timed out

听说是ssl wss的情况下才会出现，来自 @around-gao 的解决方法：
把MyWebSocketHandler和WebSocketServerProtocolHandler调下顺序就好了。