导入依赖

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

需要创建的类就两个一个config配置类一个连接类

@Configuration
@EnableWebSocket
public class WebsocketConfig {

/**
     * ServerEndpointExporter作用
     * 扫描注册ServerEndpoint
     * 这个Bean会自动注册使用@ServerEndpoint注解声明的websocket endpoint
     *
     * @return
     */
	@Bean
	public ServerEndpointExporter serverEndpointExporter() {
		return new ServerEndpointExporter();
	}
}

@Component
@ServerEndpoint(value = "/alarm/websocket-server/{uid}")
public class WebsocketService {
//    //记忆id比记忆session更方便
    private String uid;
    // 静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    private static int onlineCount = 0;
    // concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。若要实现服务端与单一客户端通信的话，可以使用Map来存放，其中Key可以为用户标识
    private static ConcurrentHashMap<String,WebsocketService> websocketMap = new ConcurrentHashMap<>();
    // 与某个客户端的连接会话，需要通过它来给客户端发送数据
    private Session session;

	private int o;

    @OnOpen
    public void onOpen(@PathParam("uid") String uid, Session session) {
        this.session = session;
        this.uid = uid;
		System.err.println(uid+"已连接");
		websocketMap.put(uid,this);
        addOnlineCount();

    }

    @OnClose
    public void onClose() {
		websocketMap.remove(this.uid);
		System.err.println(this+"断开连接");
        subOnlineCount();
    }


    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        error.printStackTrace();
    }



    /**
     * 单点发送
     *
     * @param message
     * @param uid
     */
    public void sendMessage(String message, String uid) {
		String[] uidS = uid.split(",");
		for (String id:uidS) {
			if (websocketMap.containsKey(id)){
				WebsocketService websocketService = websocketMap.get(id);
				websocketService.session.getAsyncRemote().sendText(message);
			}
		}

    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }
    public static synchronized void addOnlineCount() {
        onlineCount++;
    }
    public static synchronized void subOnlineCount() {
        onlineCount--;
    }
}

直接根据传入的id进行实现长连接然后发不同的消息，需要发消息直接调用sendMessage传入ids即可发送给对应的连接。

启动

2023-12-29 09:47:14.033  WARN 27504 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'serverEndpointExporter' defined in class path resource [org/springblade/notice/webSocket/WebsocketConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: javax.websocket.server.ServerContainer not available
2023-12-29 09:47:20.043  INFO 27504 --- [           main] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closing ...
2023-12-29 09:47:20.047  INFO 27504 --- [           main] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closed
2023-12-29 09:47:20.066  INFO 27504 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2023-12-29 09:47:20.070  WARN 27504 --- [           main] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [RxIoScheduler-1 (Evictor)] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:748)
2023-12-29 09:47:20.083  INFO 27504 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-12-29 09:47:20.093 ERROR 27504 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'serverEndpointExporter' defined in class path resource [org/springblade/notice/webSocket/WebsocketConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: javax.websocket.server.ServerContainer not available
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1794)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:897)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:405)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
    at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:140)
    at org.springblade.core.launch.BladeApplication.run(BladeApplication.java:50)
    at org.springblade.NoticeApplication.main(NoticeApplication.java:37)
Caused by: java.lang.IllegalStateException: javax.websocket.server.ServerContainer not available
    at org.springframework.util.Assert.state(Assert.java:76)
    at org.springframework.web.socket.server.standard.ServerEndpointExporter.afterPropertiesSet(ServerEndpointExporter.java:107)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1853)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1790)
    ... 16 common frames omitted

 这里启动直接报错，网上搜了一下说什么test测试需要修改，我根本没用到那玩儿

stopping service [Tomcat]

 The web application [ROOT] appears to have started a thread named [RxIoScheduler-1 (Evictor)] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)

仔细看了一下应该是有冲突，跟tomcat冲突导致

进入websocket依赖内部发现引了start-web，可能跟项目现有的冲突，直接用依赖排除注解

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

再次启动，启动成功！不报错