spring boot @Async No qualifying ****expected single found 2 applicationTaskExecutor,taskScheduler

使用spring boot  的 倆個註解時：

@EnableAsync
@Async

當一個線程多次重複調用時出現異常：

org.springframework.aop.interceptor.AsyncExecutionAspectSupport.getDefaultExecutor(AsyncExecutionAspectSupport.java:236) : Could not find unique TaskExecutor bean
org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'org.springframework.core.task.TaskExecutor' available: expected single matching bean but found 2: applicationTaskExecutor,taskScheduler
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1148)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveBean(DefaultListableBeanFactory.java:413)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:346)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:339)
	at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.getDefaultExecutor(AsyncExecutionAspectSupport.java:233)
	at org.springframework.aop.interceptor.AsyncExecutionInterceptor.getDefaultExecutor(AsyncExecutionInterceptor.java:157)
	at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$configure$2(AsyncExecutionAspectSupport.java:119)
	at org.springframework.util.function.SingletonSupplier.get(SingletonSupplier.java:100)
	at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.determineAsyncExecutor(AsyncExecutionAspectSupport.java:172)
	at org.springframework.aop.interceptor.AsyncExecutionInterceptor.invoke(AsyncExecutionInterceptor.java:107)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689)
	at com.tuijie.goods.biz.jointstore.store.products.mountain.MountainServiceImpl$$EnhancerBySpringCGLIB$$893511f8.store(<generated>)

 根據異常提示信息: 期望一個單列Bean 但是 找到了倆個相匹配的  bean.。所以報錯.

但是使用這個 Bean 是直接使用的 spirng 的，根本沒有在項目中定義，所以想要知道原因，需要去 生成Bean 的地方看看。

找到代碼的地址 org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration#applicationTaskExecutor

	@Lazy
	@Bean(name = { APPLICATION_TASK_EXECUTOR_BEAN_NAME,
			AsyncAnnotationBeanPostProcessor.DEFAULT_TASK_EXECUTOR_BEAN_NAME })
	@ConditionalOnMissingBean(Executor.class)
	public ThreadPoolTaskExecutor applicationTaskExecutor(TaskExecutorBuilder builder) {
		return builder.build();
	}

原來 bean 創建的時候有倆個 name ，這倆個 name 剛好對應: applicationTaskExecutor, taskExecutor, 也對應倆個 BeanDefinition.  Spring 在選用時候 不知道用哪個，報錯。

點進去 @Async 裏面說明

其 value 可以指定  Bean Definition 。加上

 @Async(value = "applicationTaskExecutor")

運行項目。解決