Spring WebSocket简单示例 - java.lang.IllegalStateException:意外使用调度程序

Question

我正在尝试在不使用STOMP的情况下在Spring中实现WebSocket服务器,请阅读以下文章:http://www.devglan.com/spring-boot/spring-websocket-integration-example-without-stomp

WebSocketConfig.java

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

    @Autowired private WebSocketHandler webSocketHandler;

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(webSocketHandler, "/app");
    }

}

WebSocketHandler

@Component
public class WebSocketHandler extends TextWebSocketHandler {

    private List<WebSocketSession> sessions = new CopyOnWriteArrayList<>();

    @Override
    public void afterConnectionEstablished(WebSocketSession session) {
        sessions.add(session);
    }

    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws IOException {
        // ...
    }

}

但是,我在启动时遇到此异常:

java.lang.IllegalStateException: Unexpected use of scheduler.
at org.springframework.web.socket.config.annotation.WebSocketConfigurationSupport$NoOpScheduler.schedule(WebSocketConfigurationSupport.java:108) ~[spring-websocket-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.config.ScheduledTaskRegistrar.scheduleCronTask(ScheduledTaskRegistrar.java:414) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.config.ScheduledTaskRegistrar.scheduleTasks(ScheduledTaskRegistrar.java:352) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.config.ScheduledTaskRegistrar.afterPropertiesSet(ScheduledTaskRegistrar.java:332) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.finishRegistration(ScheduledAnnotationBeanPostProcessor.java:280) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.onApplicationEvent(ScheduledAnnotationBeanPostProcessor.java:211) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.onApplicationEvent(ScheduledAnnotationBeanPostProcessor.java:102) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:399) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:353) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:887) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:161) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:552) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE]
at my.package.App.main(App.java:31) [main/:na]

如何使这个简单的WebSocket应用程序工作？

Answer 1

https://github.com/spring-projects/spring-boot/issues/12814

"没有进一步配置的@EnableWebSocket可能会创建一个no op调度程序,它将与任务调度程序的任何其他用法冲突."

这应该添加到配置中:

@Bean
public TaskScheduler taskScheduler() {
    return new ConcurrentTaskScheduler(Executors.newSingleThreadScheduledExecutor());
}