1.引入依赖

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

2.编写配置文件

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

/**
 * websocket配置文件
 *
 * @author LJH
 * @since 2023-03-10
 */
@Component
public class WebSocketConfig {
          
   

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

    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
          
   
        return new ServerEndpointExporter();
    }
}

3.编写WebSocket服务

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

@Component
@Slf4j
@ServerEndpoint("/screen/webSocket/{sid}")			// WebSocket服务地址
public class WebSocketServer {
          
   

    private Session session;

    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<>();

    private String sid;// sid，用于区分不同的连接

	// 建立连接
    @OnOpen
    public void onOpen(Session session, @PathParam("sid") String sid) {
          
   
        this.session = session;
        webSocketSet.add(this);
        this.sid = sid;
        log.info("[WebSocket消息]有新的连接，总数：{}", webSocketSet.size());
    }

	// 连接关闭
    @OnClose
    public void onClose() {
          
   
        webSocketSet.remove(this);
        log.info("[WebSocket消息]连接断开，总数：{}", webSocketSet.size());
    }

    @OnMessage
    public void onMessage(String message) {
          
   
        log.info("[WebSocket消息]收到客户端发来的消息：{}", message);
    }

    /**
     * 发送消息
     *
     * @param message 消息内容
     * @param sid      设备sid
     */
    public void sendMessage(String message, String sid) {
          
   
        for (WebSocketServer webSocket : webSocketSet) {
          
   
            log.info("[WebSocket消息]向客户端发送消息：message={}", message);
            try {
          
   
                // 针对不同的连接推送数据，广播模式注释if即可
                if (StringUtils.equals(webSocket.sid, sid)) {
          
   
                    webSocket.session.getBasicRemote().sendText(message);
                }
            } catch (IOException e) {
          
   
                log.info("WebSocket 出错了！！！");
                e.printStackTrace();
            }
        }
    }

}