base:
  config:
    nacos:
      nacoshost: localhost
      port: 8848

spring:
  application:
    name: gateway
  main:
    allow-bean-definition-overriding: true
  cloud:
    nacos:
      discovery:
        server-addr: ${base.config.nacos.nacoshost}:${base.config.nacos.port}
    gateway:
      discovery:
        locator:
          enabled: true
      routes:
        #  websocket
        - id: CLOUD-WEBSOCKET
          uri: lb:ws://cloud-websocket
          predicates:
            - Path=/cloud-websocket/**
server:
  port: 8888

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

@Configuration
@EnableWebSocket
public class WebsocketConfiguration implements WebSocketConfigurer {
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        // webSocket通道
        // 指定處理器和路徑
        registry.addHandler(new WebSocketHandler(), "/websocket")
                // 指定自定義攔截器
                .addInterceptors(new WebSocketInterceptor())
                // 允許跨域
                .setAllowedOrigins("*");
        // sockJs通道
        registry.addHandler(new WebSocketHandler(), "/sock-js")
                .addInterceptors(new WebSocketInterceptor())
                .setAllowedOrigins("*")
                // 開啟sockJs支持
                .withSockJS();
    }
}

package com.auexpress.cloud.handler;

import com.alibaba.fastjson.JSONObject;
import org.apache.commons.lang3.StringUtils;
import org.springframework.web.socket.*;
import org.springframework.web.socket.handler.AbstractWebSocketHandler;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @Description
 * @ClassName WebSocketHandler
 * @Author HYSong
 * @date 2020.04.14 10:08
 */
public class WebSocketHandler extends AbstractWebSocketHandler {
    /**
     *  存儲(chǔ)sessionId和webSocketSession
     *  需要注意的是，webSocketSession沒有提供無參構(gòu)造，不能進(jìn)行序列化，也就不能通過redis存儲(chǔ)
     *  在分布式系統(tǒng)中，要想別的辦法實(shí)現(xiàn)webSocketSession共享
     */
    private static Map<String, WebSocketSession> sessionMap = new ConcurrentHashMap<>();
    private static Map<String, String> userMap = new ConcurrentHashMap<>();

    /**
     * webSocket連接創(chuàng)建后調(diào)用
     */
    @Override
    public void afterConnectionEstablished(WebSocketSession session) {
        // 獲取參數(shù)
        String user = String.valueOf(session.getAttributes().get("user"));
        userMap.put(user, session.getId());
        sessionMap.put(session.getId(), session);
    }

    /**
     * 接收到消息會(huì)調(diào)用
     */
    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
        JSONObject jsonObject = JSONObject.parseObject(message.getPayload().toString());
        String content = jsonObject.getString("content");
        String targetAdminId = jsonObject.getString("targetId");
        if("0".equals(targetAdminId)){
            //  推送給所有人
            userMap.forEach((key,value)->{
                try {
                    this.sendMessage(key,content);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            });
        }else{
            sendMessage("1", content);
        }
    }

    /**
     * 連接出錯(cuò)會(huì)調(diào)用
     */
    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) {
        sessionMap.remove(session.getId());
    }

    /**
     * 連接關(guān)閉會(huì)調(diào)用
     */
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
        sessionMap.remove(session.getId());
    }

    @Override
    public boolean supportsPartialMessages() {
        return false;
    }

    /**
     * 后端發(fā)送消息
     */
    public void sendMessage(String user, String message) throws IOException {
        String sessionId = userMap.get(user);
        if (StringUtils.isEmpty(sessionId)) {
            return;
        }
        WebSocketSession session = sessionMap.get(sessionId);
        if (session == null) {
            return;
        }
        session.sendMessage(new TextMessage(message));
    }
}

package com.auexpress.cloud.interceptor;

import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;

import java.util.Map;

/**
 * @Description
 * @ClassName WebSocketInterceptor
 * @Author HYSong
 * @date 2020.04.14 10:09
 */
public class WebSocketInterceptor implements HandshakeInterceptor {
    /**
     * handler處理前調(diào)用,attributes屬性最終在WebSocketSession里,
     * 可能通過webSocketSession.getAttributes().get(key值)獲得
     */
    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) {
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest serverHttpRequest = (ServletServerHttpRequest) request;
            // 獲取請(qǐng)求路徑攜帶的參數(shù)
            String user = serverHttpRequest.getServletRequest().getParameter("user");
            attributes.put("user", user);
            return true;
        } else {
            return false;
        }
    }

    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {

    }
}