SpringBoot+Netty+WebSocket实现消息发送的示例代码

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

@Component
public class WebSocketServer {

 /**
  * 主线程池
  */
 private EventLoopGroup bossGroup;
 /**
  * 工作线程池
  */
 private EventLoopGroup workerGroup;
 /**
  * 服务器
  */
 private ServerBootstrap server;
 /**
  * 回调
  */
 private ChannelFuture future;

 public void start() {
  future = server.bind(9001);
  System.out.println("netty server - 启动成功");
 }

 public WebSocketServer() {
  bossGroup = new NioEventLoopGroup();
  workerGroup = new NioEventLoopGroup();

  server = new ServerBootstrap();
  server.group(bossGroup, workerGroup)
    .channel(NioServerSocketChannel.class)
    .childHandler(new WebsocketInitializer());
 }
}

public class WebsocketInitializer extends ChannelInitializer<SocketChannel> {
 
 @Override
 protected void initChannel(SocketChannel ch) throws Exception {
  ChannelPipeline pipeline = ch.pipeline();
  // ------------------
  // 用于支持Http协议
  // ------------------
  // websocket基于http协议，需要有http的编解码器
  pipeline.addLast(new HttpServerCodec());
  // 对写大数据流的支持
  pipeline.addLast(new ChunkedWriteHandler());
  // 添加对HTTP请求和响应的聚合器:只要使用Netty进行Http编程都需要使用
  //设置单次请求的文件的大小
  pipeline.addLast(new HttpObjectAggregator(1024 * 64));
  //webSocket 服务器处理的协议，用于指定给客户端连接访问的路由 :/ws
  pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));
  // 添加Netty空闲超时检查的支持
  // 1. 读空闲超时（超过一定的时间会发送对应的事件消息）
  // 2. 写空闲超时
  // 3. 读写空闲超时
  pipeline.addLast(new IdleStateHandler(4, 8, 12));
  //添加心跳处理
  pipeline.addLast(new HearBeatHandler());
  // 添加自定义的handler
  pipeline.addLast(new ChatHandler());

 }
}

@Component
public class NettyListener implements ApplicationListener<ContextRefreshedEvent> {

 @Resource
 private WebSocketServer websocketServer;

 @Override
 public void onApplicationEvent(ContextRefreshedEvent event) {
  if(event.getApplicationContext().getParent() == null) {
   try {
    websocketServer.start();
   } catch (Exception e) {
    e.printStackTrace();
   }
  }
 }
}

public class UserChannelMap {
 /**
  * 用户保存用户id与通道的Map对象
  */
// private static Map<String, Channel> userChannelMap;

 /* static {
  userChannelMap = new HashMap<String, Channel>();
 }*/

 /**
  * 定义一个channel组，管理所有的channel
  * GlobalEventExecutor.INSTANCE 是全局的事件执行器，是一个单例
  */
 private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

 /**
  * 存放用户与Chanel的对应信息，用于给指定用户发送消息
  */
 private static ConcurrentHashMap<String,Channel> userChannelMap = new ConcurrentHashMap<>();

 private UserChannelMap(){}
 /**
  * 添加用户id与channel的关联
  * @param userNum
  * @param channel
  */
 public static void put(String userNum, Channel channel) {
  userChannelMap.put(userNum, channel);
 }

 /**
  * 根据用户id移除用户id与channel的关联
  * @param userNum
  */
 public static void remove(String userNum) {
  userChannelMap.remove(userNum);
 }

 /**
  * 根据通道id移除用户与channel的关联
  * @param channelId 通道的id
  */
 public static void removeByChannelId(String channelId) {
  if(!StringUtils.isNotBlank(channelId)) {
   return;
  }
  for (String s : userChannelMap.keySet()) {
   Channel channel = userChannelMap.get(s);
   if(channelId.equals(channel.id().asLongText())) {
    System.out.println("客户端连接断开,取消用户" + s + "与通道" + channelId + "的关联");
    userChannelMap.remove(s);
    UserService userService = SpringUtil.getBean(UserService.class);
    userService.logout(s);
    break;
   }
  }
 }

 /**
  * 打印所有的用户与通道的关联数据
  */
 public static void print() {
  for (String s : userChannelMap.keySet()) {
   System.out.println("用户id:" + s + " 通道:" + userChannelMap.get(s).id());
  }
 }

 /**
  * 根据好友id获取对应的通道
  * @param receiverNum 接收人编号
  * @return Netty通道
  */
 public static Channel get(String receiverNum) {
  return userChannelMap.get(receiverNum);
 }

 /**
  * 获取channel组
  * @return
  */
 public static ChannelGroup getChannelGroup() {
  return channelGroup;
 }

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

public class Message {
 /**
  * 消息类型
  */
 private Integer type;
 /**
  * 聊天消息
  */
 private String message;
 /**
  * 扩展消息字段
  */
 private Object ext;
 public Integer getType() {
  return type;
 }

 public void setType(Integer type) {
  this.type = type;
 }

 public MarketChatRecord getChatRecord() {
  return marketChatRecord;
 }
 public void setChatRecord(MarketChatRecord chatRecord) {
  this.marketChatRecord = chatRecord;
 }

 public Object getExt() {
  return ext;
 }

 public void setExt(Object ext) {
  this.ext = ext;
 }

 @Override
 public String toString() {
  return "Message{" +
    "type=" + type +
    ", marketChatRecord=" + marketChatRecord +
    ", ext=" + ext +
    '}';
 }

}

public class ChatHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
 private static final Logger log = LoggerFactory.getLogger(WebSocketServer.class);


 /**
  * 用来保存所有的客户端连接
  */
 private static ChannelGroup clients = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

 /**
  *当Channel中有新的事件消息会自动调用
  */
 @Override
 protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
  // 当接收到数据后会自动调用
  // 获取客户端发送过来的文本消息
  Gson gson = new Gson();
  log.info("服务器收到消息：{}",msg.text());
  System.out.println("接收到消息数据为：" + msg.text());
  Message message = gson.fromJson(msg.text(), Message.class); 
//根据业务要求进行消息处理
  switch (message.getType()) {
   // 处理客户端连接的消息
   case 0:
    // 建立用户与通道的关联
   // 处理客户端发送好友消息
    break;
   case 1:
   // 处理客户端的签收消息
    break;
   case 2:
    // 将消息记录设置为已读
    break;
   case 3:
    // 接收心跳消息
    break;
   default:
    break;
  }

 }

 // 当有新的客户端连接服务器之后，会自动调用这个方法
 @Override
 public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
  log.info("handlerAdded 被调用"+ctx.channel().id().asLongText());
  // 添加到channelGroup 通道组
  UserChannelMap.getChannelGroup().add(ctx.channel());
//  clients.add(ctx.channel());
 }

 @Override
 public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
  log.info("{异常:}"+cause.getMessage());
  // 删除通道
  UserChannelMap.getChannelGroup().remove(ctx.channel());
  UserChannelMap.removeByChannelId(ctx.channel().id().asLongText());
  ctx.channel().close();
 }

 @Override
 public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
  log.info("handlerRemoved 被调用"+ctx.channel().id().asLongText());
  //删除通道
  UserChannelMap.getChannelGroup().remove(ctx.channel());
  UserChannelMap.removeByChannelId(ctx.channel().id().asLongText());
  UserChannelMap.print();
 }

}

public class HearBeatHandler extends ChannelInboundHandlerAdapter {

 @Override
 public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
  if(evt instanceof IdleStateEvent) {
   IdleStateEvent idleStateEvent = (IdleStateEvent)evt;

   if(idleStateEvent.state() == IdleState.READER_IDLE) {
    System.out.println("读空闲事件触发...");
   }
   else if(idleStateEvent.state() == IdleState.WRITER_IDLE) {
    System.out.println("写空闲事件触发...");
   }
   else if(idleStateEvent.state() == IdleState.ALL_IDLE) {
    System.out.println("---------------");
    System.out.println("读写空闲事件触发");
    System.out.println("关闭通道资源");
    ctx.channel().close();
   }
  }
 }
}