springboot開啟定時任務啟動輸出異常,但功能正常
NoSuchBeanDefinitionException: No qualifying bean of type 'java.util.concurrent.ScheduledExecutorService' available
分析
雖然沒有影響系統,但是有異常看着總歸很難受,於是嘗試去探究下這個異常的原因。
通過觀察我們這兩個異常是日志模塊打印出來的debug級別日志
2018-09-29 15:54:05,187 DEBUG main org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor [//] Could not find default TaskScheduler bean
2018-09-29 15:54:05,190 DEBUG main org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor [//] Could not find default ScheduledExecutorService bean
而且都是在ScheduledAnnotationBeanPostProcessor類中打印出來。看類的名字我們大概能猜到這是@Scheduled注解的處理類。
根據日志內容我們定位到這個問題是由finishRegistration()方法打印出來。
private void finishRegistration() { if (this.scheduler != null) { this.registrar.setScheduler(this.scheduler); } if (this.beanFactory instanceof ListableBeanFactory) { Map<String, SchedulingConfigurer> configurers = ((ListableBeanFactory)this.beanFactory).getBeansOfType(SchedulingConfigurer.class); Iterator var2 = configurers.values().iterator(); while(var2.hasNext()) { SchedulingConfigurer configurer = (SchedulingConfigurer)var2.next(); configurer.configureTasks(this.registrar); } } if (this.registrar.hasTasks() && this.registrar.getScheduler() == null) { Assert.state(this.beanFactory != null, "BeanFactory must be set to find scheduler by type"); try { this.registrar.setTaskScheduler((TaskScheduler)this.resolveSchedulerBean(TaskScheduler.class, false)); } catch (NoUniqueBeanDefinitionException var8) { try { this.registrar.setTaskScheduler((TaskScheduler)this.resolveSchedulerBean(TaskScheduler.class, true)); } catch (NoSuchBeanDefinitionException var7) { if (this.logger.isInfoEnabled()) { this.logger.info("More than one TaskScheduler bean exists within the context, and none is named ‘taskScheduler‘. Mark one of them as primary or name it ‘taskScheduler‘ (possibly as an alias); or implement the SchedulingConfigurer interface and call ScheduledTaskRegistrar#setScheduler explicitly within the configureTasks() callback: " + var8.getBeanNamesFound()); } } } catch (NoSuchBeanDefinitionException var9) { this.logger.debug("Could not find default TaskScheduler bean", var9); try { this.registrar.setScheduler(this.resolveSchedulerBean(ScheduledExecutorService.class, false)); } catch (NoUniqueBeanDefinitionException var5) { try { this.registrar.setScheduler(this.resolveSchedulerBean(ScheduledExecutorService.class, true)); } catch (NoSuchBeanDefinitionException var4) { if (this.logger.isInfoEnabled()) { this.logger.info("More than one ScheduledExecutorService bean exists within the context, and none is named ‘taskScheduler‘. Mark one of them as primary or name it ‘taskScheduler‘ (possibly as an alias); or implement the SchedulingConfigurer interface and call ScheduledTaskRegistrar#setScheduler explicitly within the configureTasks() callback: " + var5.getBeanNamesFound()); } } } catch (NoSuchBeanDefinitionException var6) { this.logger.debug("Could not find default ScheduledExecutorService bean", var6); this.logger.info("No TaskScheduler/ScheduledExecutorService bean found for scheduled processing"); } } } this.registrar.afterPropertiesSet(); }
看代碼我們會發現,spring會從先從注冊過的bean中找任務調度器TaskScheduler
this.registrar.setTaskScheduler((TaskScheduler)this.resolveSchedulerBean(TaskScheduler.class, false));
如果獲取不到會拋出異常,然后打印出來
this.logger.debug("Could not find default TaskScheduler bean", var9);
然后繼續尋找定時任務的執行類ScheduledExecutorService
this.registrar.setScheduler(this.resolveSchedulerBean(ScheduledExecutorService.class, false));
如果找不到,會繼續拋出異常並打印出來
catch (NoSuchBeanDefinitionException var6) { this.logger.debug("Could not find default ScheduledExecutorService bean", var6); this.logger.info("No TaskScheduler/ScheduledExecutorService bean found for scheduled processing"); }
如此,便看到開頭我們看到的兩個異常。
看后面代碼我們會發現,如果注冊的bean中找不到,會調用scheduleTasks()方法初始化TaskScheduler,所以這兩個異常並不會影響系統。可能spring 的開發者是想借此提醒開發人員要自己在系統中注冊要使用的bean,而不是依賴框架來默認初始化。
解決辦法
修改日志級別
第一種是眼不見為凈法,簡單粗暴地修改日志級別就好。
log4j.logger.org.springframework.scheduling = INFO
這樣debug級別的日志就不會被打印出來,只有最后的info級別日志才會被打印。
注冊TaskScheduler
既然提示的異常是注冊的bean中找不到TaskScheduler,那么我們就注冊TaskScheduler。
@Bean public TaskScheduler scheduledExecutorService() { ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler(); scheduler.setPoolSize(8); scheduler.setThreadNamePrefix("scheduled-thread-"); return scheduler; }