Springboot+Netty+Websocket实现消息推送实例

前言

websocket 使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在 websocket api 中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。

netty框架的优势

 1. api使用简单，开发门槛低；
 2. 功能强大，预置了多种编解码功能，支持多种主流协议；
 3. 定制能力强，可以通过channelhandler对通信框架进行灵活地扩展；
 4. 性能高，通过与其他业界主流的nio框架对比，netty的综合性能最优；
 5. 成熟、稳定，netty修复了已经发现的所有jdk nio bug，业务开发人员不需要再为nio的bug而烦恼

提示：以下是本篇文章正文内容，下面案例可供参考

一、引入netty依赖

<dependency>
   <groupid>io.netty</groupid>
   <artifactid>netty-all</artifactid>
   <version>4.1.48.final</version>
</dependency>

二、使用步骤

1.引入基础配置类

package com.test.netty;

public enum cmd {
 start("000", "连接成功"),
 wmessage("001", "消息提醒"),
 ;
 private string cmd;
 private string desc;

 cmd(string cmd, string desc) {
  this.cmd = cmd;
  this.desc = desc;
 }

 public string getcmd() {
  return cmd;
 }

 public string getdesc() {
  return desc;
 }
}

2.netty服务启动监听器

package com.test.netty;

import io.netty.bootstrap.serverbootstrap;
import io.netty.channel.channelfuture;
import io.netty.channel.channeloption;
import io.netty.channel.eventloopgroup;
import io.netty.channel.nio.nioeventloopgroup;
import io.netty.channel.socket.nio.nioserversocketchannel;
import lombok.extern.slf4j.slf4j;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.beans.factory.annotation.value;
import org.springframework.boot.applicationrunner;
import org.springframework.context.annotation.bean;
import org.springframework.stereotype.component;

/**
 * @author test
 * <p>
 * 服务启动监听器
 **/
@slf4j
@component
public class nettyserver {

 @value("${server.netty.port}")
 private int port;

 @autowired
 private serverchannelinitializer serverchannelinitializer;

 @bean
 applicationrunner nettyrunner() {
  return args -> {
   //new 一个主线程组
   eventloopgroup bossgroup = new nioeventloopgroup(1);
   //new 一个工作线程组
   eventloopgroup workgroup = new nioeventloopgroup();
   serverbootstrap bootstrap = new serverbootstrap()
     .group(bossgroup, workgroup)
     .channel(nioserversocketchannel.class)
     .childhandler(serverchannelinitializer)
     //设置队列大小
     .option(channeloption.so_backlog, 1024)
     // 两小时内没有数据的通信时,tcp会自动发送一个活动探测数据报文
     .childoption(channeloption.so_keepalive, true);
   //绑定端口,开始接收进来的连接
   try {
    channelfuture future = bootstrap.bind(port).sync();
    log.info("服务器启动开始监听端口: {}", port);
    future.channel().closefuture().sync();
   } catch (interruptedexception e) {
    e.printstacktrace();
   } finally {
    //关闭主线程组
    bossgroup.shutdowngracefully();
    //关闭工作线程组
    workgroup.shutdowngracefully();
   }
  };
 }
}

3.netty服务端处理器

package com.test.netty;

import com.test.common.util.jsonutil;
import io.netty.channel.channel;
import io.netty.channel.channelhandler;
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 lombok.data;
import lombok.extern.slf4j.slf4j;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.component;

import java.net.urldecoder;
import java.util.*;

/**
 * @author test
 * <p>
 * netty服务端处理器
 **/
@slf4j
@component
@channelhandler.sharable
public class nettyserverhandler extends simplechannelinboundhandler<textwebsocketframe> {

 @autowired
 private serverchannelcache cache;
 private static final string datakey = "test=";

 @data
 public static class channelcache {
 }


 /**
  * 客户端连接会触发
  */
 @override
 public void channelactive(channelhandlercontext ctx) throws exception {
  channel channel = ctx.channel();
  log.info("通道连接已打开，id->{}......", channel.id().aslongtext());
 }

 @override
 public void usereventtriggered(channelhandlercontext ctx, object evt) throws exception {
  if (evt instanceof websocketserverprotocolhandler.handshakecomplete) {
   channel channel = ctx.channel();
   websocketserverprotocolhandler.handshakecomplete handshakecomplete = (websocketserverprotocolhandler.handshakecomplete) evt;
   string requesturi = handshakecomplete.requesturi();
   requesturi = urldecoder.decode(requesturi, "utf-8");
   log.info("handshake_complete，id->{}，uri->{}", channel.id().aslongtext(), requesturi);
   string socketkey = requesturi.substring(requesturi.lastindexof(datakey) + datakey.length());
   if (socketkey.length() > 0) {
    cache.add(socketkey, channel);
    this.send(channel, cmd.down_start, null);
   } else {
    channel.disconnect();
    ctx.close();
   }
  }
  super.usereventtriggered(ctx, evt);
 }

 @override
 public void channelinactive(channelhandlercontext ctx) throws exception {
  channel channel = ctx.channel();
  log.info("通道连接已断开，id->{}，用户id->{}......", channel.id().aslongtext(), cache.getcacheid(channel));
  cache.remove(channel);
 }

 /**
  * 发生异常触发
  */
 @override
 public void exceptioncaught(channelhandlercontext ctx, throwable cause) throws exception {
  channel channel = ctx.channel();
  log.error("连接出现异常，id->{}，用户id->{}，异常->{}......", channel.id().aslongtext(), cache.getcacheid(channel), cause.getmessage(), cause);
  cache.remove(channel);
  ctx.close();
 }

 /**
  * 客户端发消息会触发
  */
 @override
 protected void channelread0(channelhandlercontext ctx, textwebsocketframe msg) throws exception {
  try {
   // log.info("接收到客户端发送的消息：{}", msg.text());
   ctx.channel().writeandflush(new textwebsocketframe(jsonutil.tostring(collections.singletonmap("cmd", "100"))));
  } catch (exception e) {
   log.error("消息处理异常：{}", e.getmessage(), e);
  }
 }

 public void send(cmd cmd, string id, object obj) {
  hashmap<string, channel> channels = cache.get(id);
  if (channels == null) {
   return;
  }
  map<string, object> data = new linkedhashmap<>();
  data.put("cmd", cmd.getcmd());
  data.put("data", obj);
  string msg = jsonutil.tostring(data);
  log.info("服务器下发消息: {}", msg);
  channels.values().foreach(channel -> {
   channel.writeandflush(new textwebsocketframe(msg));
  });
 }

 public void send(channel channel, cmd cmd, object obj) {
  map<string, object> data = new linkedhashmap<>();
  data.put("cmd", cmd.getcmd());
  data.put("data", obj);
  string msg = jsonutil.tostring(data);
  log.info("服务器下发消息: {}", msg);
  channel.writeandflush(new textwebsocketframe(msg));
 }

}

4.netty服务端缓存类

package com.test.netty;

import io.netty.channel.channel;
import io.netty.util.attributekey;
import org.springframework.stereotype.component;

import java.util.hashmap;
import java.util.concurrent.concurrenthashmap;

@component
public class serverchannelcache {
 private static final concurrenthashmap<string, hashmap<string, channel>> cache_map = new concurrenthashmap<>();
 private static final attributekey<string> channel_attr_key = attributekey.valueof("test");

 public string getcacheid(channel channel) {
  return channel.attr(channel_attr_key).get();
 }

 public void add(string cacheid, channel channel) {
  channel.attr(channel_attr_key).set(cacheid);
  hashmap<string, channel> hashmap = cache_map.get(cacheid);
  if (hashmap == null) {
   hashmap = new hashmap<>();
  }
  hashmap.put(channel.id().asshorttext(), channel);
  cache_map.put(cacheid, hashmap);
 }

 public hashmap<string, channel> get(string cacheid) {
  if (cacheid == null) {
   return null;
  }
  return cache_map.get(cacheid);
 }

 public void remove(channel channel) {
  string cacheid = getcacheid(channel);
  if (cacheid == null) {
   return;
  }
  hashmap<string, channel> hashmap = cache_map.get(cacheid);
  if (hashmap == null) {
   hashmap = new hashmap<>();
  }
  hashmap.remove(channel.id().asshorttext());
  cache_map.put(cacheid, hashmap);
 }
}

5.netty服务初始化器

package com.test.netty;

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;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.component;

/**
 * @author test
 * <p>
 * netty服务初始化器
 **/
@component
public class serverchannelinitializer extends channelinitializer<socketchannel> {

 @autowired
 private nettyserverhandler nettyserverhandler;

 @override
 protected void initchannel(socketchannel socketchannel) throws exception {
  channelpipeline pipeline = socketchannel.pipeline();
  pipeline.addlast(new httpservercodec());
  pipeline.addlast(new chunkedwritehandler());
  pipeline.addlast(new httpobjectaggregator(8192));
  pipeline.addlast(new websocketserverprotocolhandler("/test.io", true, 5000));
  pipeline.addlast(nettyserverhandler);
 }
}

6.html测试

<!doctype html>
<html>
 <head>
 <meta charset="utf-8">
 <title>test</title>
 
  <script type="text/javascript">
   function websockettest()
   {
   if ("websocket" in window)
   {
    alert("您的浏览器支持 websocket!");
    
    // 打开一个 web socket
    var ws = new websocket("ws://localhost:port/test.io");
    
    ws.onopen = function()
    {
     // web socket 已连接上，使用 send() 方法发送数据
     ws.send("发送数据");
     alert("数据发送中...");
    };
    
    ws.onmessage = function (evt) 
    { 
     var received_msg = evt.data;
     alert("数据已接收...");
    };
    
    ws.onclose = function()
    { 
     // 关闭 websocket
     alert("连接已关闭..."); 
    };
   }
   
   else
   {
    // 浏览器不支持 websocket
    alert("您的浏览器不支持 websocket!");
   }
   }
  </script>
  
 </head>
 <body>
 
  <div id="sse">
   <a href="javascript:websockettest()" rel="external nofollow" >运行 websocket</a>
  </div>
  
 </body>
</html>

7.vue测试

mounted() {
   this.initwebsocket();
  },
  methods: {
   initwebsocket() {
    let websocket = new websocket('ws://localhost:port/test.io?test=123456');
    websocket.onmessage = (event) => {
     let msg = json.parse(event.data);
     switch (msg.cmd) {
      case "000":
       this.$message({
        type: 'success',
        message: "建立实时连接成功！",
        duration: 1000
       })
       setinterval(()=>{websocket.send("heartbeat")},60*1000);
       break;
      case "001":
       this.$message.warning("收到一条新的信息，请及时查看！")
       break;
     }
    }
    websocket.onclose = () => {
     settimeout(()=>{
      this.initwebsocket();
     },30*1000);
    }
    websocket.onerror = () => {
     settimeout(()=>{
      this.initwebsocket();
     },30*1000);
    }
   },
  },
![在这里插入图片描述](https://img-blog.csdnimg.cn/20210107160420568.jpg?x-oss-process=image/watermark,type_zmfuz3pozw5nagvpdgk,shadow_10,text_ahr0chm6ly9ibg9nlmnzzg4ubmv0l3d1x3fpbmdfc29uzw==,size_16,color_ffffff,t_70#pic_center)

8.服务器下发消息

@autowired
	private nettyserverhandler nettyserverhandler;
nettyserverhandler.send(cmdweb.wmessage, id, message);

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