SpringBoot+WebSocket+Netty實現(xiàn)消息推送的方法

<dependency>
 <groupId>io.netty</groupId>
 <artifactId>netty-all</artifactId> 
 <version>4.1.33.Final</version>
</dependency>

<dependency>
 <groupId>cn.hutool</groupId>
 <artifactId>hutool-all</artifactId>
 <version>5.2.3</version>
</dependency>

package com.sixj.nettypush.config;

import io.netty.channel.Channel;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

import java.util.concurrent.ConcurrentHashMap;

/**
 * @author sixiaojie
 * @date 2020-03-28-15:07
 */
public class NettyConfig {
  /**
   * 定義一個channel組，管理所有的channel
   * GlobalEventExecutor.INSTANCE 是全局的事件執(zhí)行器，是一個單例
   */
  private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

  /**
   * 存放用戶與Chanel的對應(yīng)信息，用于給指定用戶發(fā)送消息
   */
  private static ConcurrentHashMap<String,Channel> userChannelMap = new ConcurrentHashMap<>();

  private NettyConfig() {}
  
  /**
   * 獲取channel組
   * @return
   */
  public static ChannelGroup getChannelGroup() {
    return channelGroup;
  }

  /**
   * 獲取用戶channel map
   * @return
   */
  public static ConcurrentHashMap<String,Channel> getUserChannelMap(){
    return userChannelMap;
  }
}

package com.sixj.nettypush.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
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.serialization.ObjectEncoder;
import io.netty.handler.stream.ChunkedWriteHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import java.net.InetSocketAddress;

/**
 * @author sixiaojie
 * @date 2020-03-28-13:44
 */

@Component
public class NettyServer{
  private static final Logger log = LoggerFactory.getLogger(NettyServer.class);
  /**
   * webSocket協(xié)議名
   */
  private static final String WEBSOCKET_PROTOCOL = "WebSocket";

  /**
   * 端口號
   */
  @Value("${webSocket.netty.port:58080}")
  private int port;

  /**
   * webSocket路徑
   */
  @Value("${webSocket.netty.path:/webSocket}")
  private String webSocketPath;

  @Autowired
  private WebSocketHandler webSocketHandler;

  private EventLoopGroup bossGroup;
  private EventLoopGroup workGroup;

  /**
   * 啟動
   * @throws InterruptedException
   */
  private void start() throws InterruptedException {
    bossGroup = new NioEventLoopGroup();
    workGroup = new NioEventLoopGroup();
    ServerBootstrap bootstrap = new ServerBootstrap();
    // bossGroup輔助客戶端的tcp連接請求, workGroup負責(zé)與客戶端之前的讀寫操作
    bootstrap.group(bossGroup,workGroup);
    // 設(shè)置NIO類型的channel
    bootstrap.channel(NioServerSocketChannel.class);
    // 設(shè)置監(jiān)聽端口
    bootstrap.localAddress(new InetSocketAddress(port));
    // 連接到達時會創(chuàng)建一個通道
    bootstrap.childHandler(new ChannelInitializer<SocketChannel>() {

      @Override
      protected void initChannel(SocketChannel ch) throws Exception {
        // 流水線管理通道中的處理程序（Handler），用來處理業(yè)務(wù)
        // webSocket協(xié)議本身是基于http協(xié)議的，所以這邊也要使用http編解碼器
        ch.pipeline().addLast(new HttpServerCodec());
        ch.pipeline().addLast(new ObjectEncoder());
        // 以塊的方式來寫的處理器
        ch.pipeline().addLast(new ChunkedWriteHandler());
        /*
        說明：
        1、http數(shù)據(jù)在傳輸過程中是分段的，HttpObjectAggregator可以將多個段聚合
        2、這就是為什么，當瀏覽器發(fā)送大量數(shù)據(jù)時，就會發(fā)送多次http請求
         */
        ch.pipeline().addLast(new HttpObjectAggregator(8192));
        /*
        說明：
        1、對應(yīng)webSocket，它的數(shù)據(jù)是以幀（frame）的形式傳遞
        2、瀏覽器請求時 ws://localhost:58080/xxx 表示請求的uri
        3、核心功能是將http協(xié)議升級為ws協(xié)議，保持長連接
        */
        ch.pipeline().addLast(new WebSocketServerProtocolHandler(webSocketPath, WEBSOCKET_PROTOCOL, true, 65536 * 10));
        // 自定義的handler，處理業(yè)務(wù)邏輯
        ch.pipeline().addLast(webSocketHandler);

      }
    });
    // 配置完成，開始綁定server，通過調(diào)用sync同步方法阻塞直到綁定成功
    ChannelFuture channelFuture = bootstrap.bind().sync();
    log.info("Server started and listen on:{}",channelFuture.channel().localAddress());
    // 對關(guān)閉通道進行監(jiān)聽
    channelFuture.channel().closeFuture().sync();
  }

  /**
   * 釋放資源
   * @throws InterruptedException
   */
  @PreDestroy
  public void destroy() throws InterruptedException {
    if(bossGroup != null){
      bossGroup.shutdownGracefully().sync();
    }
    if(workGroup != null){
      workGroup.shutdownGracefully().sync();
    }
  }
  @PostConstruct()
  public void init() {
    //需要開啟一個新的線程來執(zhí)行netty server 服務(wù)器
    new Thread(() -> {
      try {
        start();
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }).start();
  }
}

package com.sixj.nettypush.websocket;

import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.sixj.nettypush.config.NettyConfig;
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.util.AttributeKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;


/**
 * TextWebSocketFrame類型， 表示一個文本幀
 * @author sixiaojie
 * @date 2020-03-28-13:47
 */
@Component
@ChannelHandler.Sharable
public class WebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
  private static final Logger log = LoggerFactory.getLogger(NettyServer.class);

  /**
   * 一旦連接，第一個被執(zhí)行
   * @param ctx
   * @throws Exception
   */
  @Override
  public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
    log.info("handlerAdded 被調(diào)用"+ctx.channel().id().asLongText());
    // 添加到channelGroup 通道組
    NettyConfig.getChannelGroup().add(ctx.channel());
  }

  /**
   * 讀取數(shù)據(jù)
   */
  @Override
  protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
    log.info("服務(wù)器收到消息：{}",msg.text());

    // 獲取用戶ID,關(guān)聯(lián)channel
    JSONObject jsonObject = JSONUtil.parseObj(msg.text());
    String uid = jsonObject.getStr("uid");
    NettyConfig.getUserChannelMap().put(uid,ctx.channel());

    // 將用戶ID作為自定義屬性加入到channel中，方便隨時channel中獲取用戶ID
    AttributeKey<String> key = AttributeKey.valueOf("userId");
    ctx.channel().attr(key).setIfAbsent(uid);

    // 回復(fù)消息
    ctx.channel().writeAndFlush(new TextWebSocketFrame("服務(wù)器連接成功！"));
  }

  @Override
  public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
    log.info("handlerRemoved 被調(diào)用"+ctx.channel().id().asLongText());
    // 刪除通道
    NettyConfig.getChannelGroup().remove(ctx.channel());
    removeUserId(ctx);
  }

  @Override
  public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    log.info("異常：{}",cause.getMessage());
    // 刪除通道
    NettyConfig.getChannelGroup().remove(ctx.channel());
    removeUserId(ctx);
    ctx.close();
  }

  /**
   * 刪除用戶與channel的對應(yīng)關(guān)系
   * @param ctx
   */
  private void removeUserId(ChannelHandlerContext ctx){
    AttributeKey<String> key = AttributeKey.valueOf("userId");
    String userId = ctx.channel().attr(key).get();
    NettyConfig.getUserChannelMap().remove(userId);
  }
}

**第四步：**具體消息推送的接口
public interface PushService {
  /**
   * 推送給指定用戶
   * @param userId
   * @param msg
   */
  void pushMsgToOne(String userId,String msg);

  /**
   * 推送給所有用戶
   * @param msg
   */
  void pushMsgToAll(String msg);
}

import java.util.concurrent.ConcurrentHashMap;

/**
 * @author sixiaojie
 * @date 2020-03-30-20:10
 */
@Service
public class PushServiceImpl implements PushService {

  @Override
  public void pushMsgToOne(String userId, String msg){
    ConcurrentHashMap<String, Channel> userChannelMap = NettyConfig.getUserChannelMap();
    Channel channel = userChannelMap.get(userId);
    channel.writeAndFlush(new TextWebSocketFrame(msg));
  }
  @Override
  public void pushMsgToAll(String msg){
    NettyConfig.getChannelGroup().writeAndFlush(new TextWebSocketFrame(msg));
  }
}

package com.sixj.nettypush.controller;

import com.sixj.nettypush.service.PushService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author sixiaojie
 * @date 2020-03-30-20:08
 */
@RestController
@RequestMapping("/push")
public class PushController {

  @Autowired
  private PushService pushService;

  /**
   * 推送給所有用戶
   * @param msg
   */
  @PostMapping("/pushAll")
  public void pushToAll(@RequestParam("msg") String msg){
    pushService.pushMsgToAll(msg);
  }
  /**
   * 推送給指定用戶
   * @param userId
   * @param msg
   */
  @PostMapping("/pushOne")
  public void pushMsgToOne(@RequestParam("userId") String userId,@RequestParam("msg") String msg){
    pushService.pushMsgToOne(userId,msg);
  }
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<script>
  var socket;
  // 判斷當前瀏覽器是否支持webSocket
  if(window.WebSocket){
    socket = new WebSocket("ws://192.168.174.25:58080/webSocket")
    // 相當于channel的read事件，ev 收到服務(wù)器回送的消息
    socket.onmessage = function (ev) {
      var rt = document.getElementById("responseText");
      rt.value = rt.value + "\n" + ev.data;
    }
    // 相當于連接開啟
    socket.onopen = function (ev) {
      var rt = document.getElementById("responseText");
      rt.value = "連接開啟了..."
      socket.send(
        JSON.stringify({
          // 連接成功將，用戶ID傳給服務(wù)端
          uid: "123456"
        })
      );
    }
    // 相當于連接關(guān)閉
    socket.onclose = function (ev) {
      var rt = document.getElementById("responseText");
      rt.value = rt.value + "\n" + "連接關(guān)閉了...";
    }
  }else{
    alert("當前瀏覽器不支持webSocket")
  }


</script>
  <form onsubmit="return false">
    <textarea id="responseText" ></textarea>
    <input type="button" value="清空內(nèi)容" onclick="document.getElementById('responseText').value=''">
  </form>
</body>
</html>