SpringBoot 整合WebSocket

简介：WebSocket是基于TCP的网络协议，它实现了服务器可以主动发送消息给客户端，当然客户端也可以给服务器发送消息。HTTP协议缺陷是通讯只能由客户端发起，以前获取消息时，是前端采用轮询方式向后端请求获取数据，这样效率低，且浪费资源，WebSocket由此诞生。

1. pom.xml Maven依赖

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

2. WebSocketConfig配置类

package com.ruhaunxingyun.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * @description: 开启WebSocket
 * @author: ruphie
 * @date: Create in 2020/3/25 14:36
 * @company: ruhuanxingyun
 */
@Configuration
public class WebSocketConfig {
    
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
    
}

 3. WebSocketServer核心类

package com.ruhuanxingyun.websocket;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @description: 发送与接收消息
 * @author: ruphie
 * @date: Create in 2020/3/27 10:33
 * @company: ruhuanxingyun
 */
@Component
@ServerEndpoint("/ws/ruhuanxingyun/{userId}")
@Slf4j
public class WebSocketServer {

    private static AtomicInteger onlineNum = new AtomicInteger();

    private static Map<Long, Session> map = new ConcurrentHashMap<>();

    /**
     * 建立连接
     *
     * @param session session
     * @param userId  用户ID
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("userId") String userId) {
        int num = onlineNum.incrementAndGet();
        map.put(Long.valueOf(userId), session);
        log.info("新建立客户端连接，sessionId为：{}，当前连接数为：{}", session.getId(), num);
    }

    /**
     * 关闭连接
     *
     * @param session session
     */
    @OnClose
    public void onClose(Session session) {
        map.values().remove(session);
        int num = onlineNum.decrementAndGet();
        log.info("sessionId为{}的客户端连接关闭，当前剩余连接数为：{}", session.getId(), num);
    }

    /**
     * 客户端发送消息
     *
     * @param session session
     * @param message 消息
     */
    @OnMessage
    public void onMessage(Session session, String message) {
        log.info("sessionId : {} , onMessage : {}", session.getId(), message);
    }

    /**
     * 发生错误
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("WebSocket发生错误：{}，Session ID： {}", error, session.getId());
    }

    /**
     * 服务器端推送消息
     *
     * @param session session
     * @param message 消息
     */
    public static void sendMessage(Session session, String message) {
        try {
            if (session.isOpen()) {
                // 同步消息
                session.getBasicRemote().sendText(message);
                // 异步消息
                //session.getAsyncRemote().sendText(message);
            }
        } catch (IOException e) {
            e.printStackTrace();
            log.error("WebSocket发送消息出错：{}", e.getMessage());
        }
    }

}

 

可参考：https://blog.lqdev.cn/2018/08/14/springboot/chapter-nineteen/