\u672c\u6587\u4e3b\u8981\u7814\u7a76\u4e00\u4e0bspring\u7684TransactionalEventListener<\/p>\n
org\/springframework\/transaction\/event\/TransactionalEventListener.java<\/p>\n
\/**\n * An {@link EventListener} that is invoked according to a {@link TransactionPhase}.\n *\n * <p>If the event is not published within an active transaction, the event is discarded\n * unless the {@link #fallbackExecution} flag is explicitly set. If a transaction is\n * running, the event is processed according to its {@code TransactionPhase}.\n *\n * <p>Adding {@link org.springframework.core.annotation.Order @Order} to your annotated\n * method allows you to prioritize that listener amongst other listeners running before\n * or after transaction completion.\n *\n * @author Stephane Nicoll\n * @author Sam Brannen\n * @since 4.2\n *\/\n@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})\n@Retention(RetentionPolicy.RUNTIME)\n@Documented\n@EventListener\npublic @interface TransactionalEventListener {\n\n \/**\n * Phase to bind the handling of an event to.\n * <p>The default phase is {@link TransactionPhase#AFTER_COMMIT}.\n * <p>If no transaction is in progress, the event is not processed at\n * all unless {@link #fallbackExecution} has been enabled explicitly.\n *\/\n TransactionPhase phase() default TransactionPhase.AFTER_COMMIT;\n\n \/**\n * Whether the event should be processed if no transaction is running.\n *\/\n boolean fallbackExecution() default false;\n\n \/**\n * Alias for {@link #classes}.\n *\/\n @AliasFor(annotation = EventListener.class, attribute = "classes")\n Class<?>[] value() default {};\n\n \/**\n * The event classes that this listener handles.\n * <p>If this attribute is specified with a single value, the annotated\n * method may optionally accept a single parameter. However, if this\n * attribute is specified with multiple values, the annotated method\n * must <em>not<\/em> declare any parameters.\n *\/\n @AliasFor(annotation = EventListener.class, attribute = "classes")\n Class<?>[] classes() default {};\n\n \/**\n * Spring Expression Language (SpEL) attribute used for making the event\n * handling conditional.\n * <p>The default is {@code ""}, meaning the event is always handled.\n * @see EventListener#condition\n *\/\n String condition() default "";\n\n}<\/code><\/pre>\nTransactionalEventListener\u662fEventListener\u7684\u4e8b\u52a1\u611f\u77e5\u7248\u672c\uff0c\u9ed8\u8ba4\u7684\u662fTransactionPhase\u662fAFTER_COMMIT<\/p><\/blockquote>\n
ApplicationListenerMethodTransactionalAdapter<\/h2>\n
org\/springframework\/transaction\/event\/ApplicationListenerMethodTransactionalAdapter.java<\/p>\n
\/**\n * {@link GenericApplicationListener} adapter that delegates the processing of\n * an event to a {@link TransactionalEventListener} annotated method. Supports\n * the exact same features as any regular {@link EventListener} annotated method\n * but is aware of the transactional context of the event publisher.\n *\n * <p>Processing of {@link TransactionalEventListener} is enabled automatically\n * when Spring's transaction management is enabled. For other cases, registering\n * a bean of type {@link TransactionalEventListenerFactory} is required.\n *\n * @author Stephane Nicoll\n * @author Juergen Hoeller\n * @since 4.2\n * @see ApplicationListenerMethodAdapter\n * @see TransactionalEventListener\n *\/\nclass ApplicationListenerMethodTransactionalAdapter extends ApplicationListenerMethodAdapter {\n\n private final TransactionalEventListener annotation;\n\n\n public ApplicationListenerMethodTransactionalAdapter(String beanName, Class<?> targetClass, Method method) {\n super(beanName, targetClass, method);\n TransactionalEventListener ann = AnnotatedElementUtils.findMergedAnnotation(method, TransactionalEventListener.class);\n if (ann == null) {\n throw new IllegalStateException("No TransactionalEventListener annotation found on method: " + method);\n }\n this.annotation = ann;\n }\n\n\n @Override\n public void onApplicationEvent(ApplicationEvent event) {\n if (TransactionSynchronizationManager.isSynchronizationActive()\n && TransactionSynchronizationManager.isActualTransactionActive()) {\n TransactionSynchronization transactionSynchronization = createTransactionSynchronization(event);\n TransactionSynchronizationManager.registerSynchronization(transactionSynchronization);\n }\n else if (this.annotation.fallbackExecution()) {\n if (this.annotation.phase() == TransactionPhase.AFTER_ROLLBACK && logger.isWarnEnabled()) {\n logger.warn("Processing " + event + " as a fallback execution on AFTER_ROLLBACK phase");\n }\n processEvent(event);\n }\n else {\n \/\/ No transactional event execution at all\n if (logger.isDebugEnabled()) {\n logger.debug("No transaction is active - skipping " + event);\n }\n }\n }\n\n private TransactionSynchronization createTransactionSynchronization(ApplicationEvent event) {\n return new TransactionSynchronizationEventAdapter(this, event, this.annotation.phase());\n }\n\n\n private static class TransactionSynchronizationEventAdapter extends TransactionSynchronizationAdapter {\n\n private final ApplicationListenerMethodAdapter listener;\n\n private final ApplicationEvent event;\n\n private final TransactionPhase phase;\n\n public TransactionSynchronizationEventAdapter(ApplicationListenerMethodAdapter listener,\n ApplicationEvent event, TransactionPhase phase) {\n\n this.listener = listener;\n this.event = event;\n this.phase = phase;\n }\n\n @Override\n public int getOrder() {\n return this.listener.getOrder();\n }\n\n @Override\n public void beforeCommit(boolean readOnly) {\n if (this.phase == TransactionPhase.BEFORE_COMMIT) {\n processEvent();\n }\n }\n\n @Override\n public void afterCompletion(int status) {\n if (this.phase == TransactionPhase.AFTER_COMMIT && status == STATUS_COMMITTED) {\n processEvent();\n }\n else if (this.phase == TransactionPhase.AFTER_ROLLBACK && status == STATUS_ROLLED_BACK) {\n processEvent();\n }\n else if (this.phase == TransactionPhase.AFTER_COMPLETION) {\n processEvent();\n }\n }\n\n protected void processEvent() {\n this.listener.processEvent(this.event);\n }\n }\n\n}<\/code><\/pre>\nApplicationListenerMethodTransactionalAdapter\u7ee7\u627f\u4e86ApplicationListenerMethodAdapter\uff0c\u5b83\u7684\u6784\u9020\u5668\u4f1a\u627e\u5230\u6307\u5b9a\u65b9\u6cd5\u7684TransactionalEventListener\u4fe1\u606f\uff1b\u5176onApplicationEvent\u65b9\u6cd5\u5728\u6709\u4e8b\u52a1\u7684\u65f6\u5019\u4f1a\u521b\u5efa\u5e76\u6ce8\u518ctransactionSynchronization\u5230\u5f53\u524d\u4e8b\u52a1\uff0c\u6ca1\u6709\u4e8b\u52a1\u82e5\u5141\u8bb8fallbackExecution\u4e5f\u4f1a\u6267\u884cprocessEvent
TransactionSynchronizationEventAdapter\u53ea\u662f\u8986\u76d6\u4e86beforeCommit\u53caafterCompletion\u4e24\u4e2a\u65b9\u6cd5\uff0c\u5728afterCompletion\u65b9\u6cd5\u4e2d\u6839\u636estatus\u7684\u503c\u4e0ephase\u7684\u503c\u7684\u5339\u914d\u5173\u7cfb\u51b3\u5b9a\u662f\u5426\u6267\u884cprocessEvent<\/p><\/blockquote>\n
TransactionalEventListenerFactory<\/h2>\n
org\/springframework\/transaction\/event\/TransactionalEventListenerFactory.java<\/p>\n
\/**\n * {@link EventListenerFactory} implementation that handles {@link TransactionalEventListener}\n * annotated methods.\n *\n * @author Stephane Nicoll\n * @since 4.2\n *\/\npublic class TransactionalEventListenerFactory implements EventListenerFactory, Ordered {\n\n private int order = 50;\n\n\n public void setOrder(int order) {\n this.order = order;\n }\n\n @Override\n public int getOrder() {\n return this.order;\n }\n\n\n @Override\n public boolean supportsMethod(Method method) {\n return AnnotatedElementUtils.hasAnnotation(method, TransactionalEventListener.class);\n }\n\n @Override\n public ApplicationListener<?> createApplicationListener(String beanName, Class<?> type, Method method) {\n return new ApplicationListenerMethodTransactionalAdapter(beanName, type, method);\n }\n\n}<\/code><\/pre>\nTransactionalEventListenerFactory\u7528\u4e8e\u521b\u5efaApplicationListenerMethodTransactionalAdapter<\/p><\/blockquote>\n
EventListenerMethodProcessor<\/h2>\n
org\/springframework\/context\/event\/EventListenerMethodProcessor.java<\/p>\n
public class EventListenerMethodProcessor\n implements SmartInitializingSingleton, ApplicationContextAware, BeanFactoryPostProcessor {\n\n \/\/......\n\n @Override\n public void afterSingletonsInstantiated() {\n ConfigurableListableBeanFactory beanFactory = this.beanFactory;\n Assert.state(this.beanFactory != null, "No ConfigurableListableBeanFactory set");\n String[] beanNames = beanFactory.getBeanNamesForType(Object.class);\n for (String beanName : beanNames) {\n if (!ScopedProxyUtils.isScopedTarget(beanName)) {\n Class<?> type = null;\n try {\n type = AutoProxyUtils.determineTargetClass(beanFactory, beanName);\n }\n catch (Throwable ex) {\n \/\/ An unresolvable bean type, probably from a lazy bean - let's ignore it.\n if (logger.isDebugEnabled()) {\n logger.debug("Could not resolve target class for bean with name '" + beanName + "'", ex);\n }\n }\n if (type != null) {\n if (ScopedObject.class.isAssignableFrom(type)) {\n try {\n Class<?> targetClass = AutoProxyUtils.determineTargetClass(\n beanFactory, ScopedProxyUtils.getTargetBeanName(beanName));\n if (targetClass != null) {\n type = targetClass;\n }\n }\n catch (Throwable ex) {\n \/\/ An invalid scoped proxy arrangement - let's ignore it.\n if (logger.isDebugEnabled()) {\n logger.debug("Could not resolve target bean for scoped proxy '" + beanName + "'", ex);\n }\n }\n }\n try {\n processBean(beanName, type);\n }\n catch (Throwable ex) {\n throw new BeanInitializationException("Failed to process @EventListener " +\n "annotation on bean with name '" + beanName + "'", ex);\n }\n }\n }\n }\n }\n\n private void processBean(final String beanName, final Class<?> targetType) {\n if (!this.nonAnnotatedClasses.contains(targetType) &&\n AnnotationUtils.isCandidateClass(targetType, EventListener.class) &&\n !isSpringContainerClass(targetType)) {\n\n Map<Method, EventListener> annotatedMethods = null;\n try {\n annotatedMethods = MethodIntrospector.selectMethods(targetType,\n (MethodIntrospector.MetadataLookup<EventListener>) method ->\n AnnotatedElementUtils.findMergedAnnotation(method, EventListener.class));\n }\n catch (Throwable ex) {\n \/\/ An unresolvable type in a method signature, probably from a lazy bean - let's ignore it.\n if (logger.isDebugEnabled()) {\n logger.debug("Could not resolve methods for bean with name '" + beanName + "'", ex);\n }\n }\n\n if (CollectionUtils.isEmpty(annotatedMethods)) {\n this.nonAnnotatedClasses.add(targetType);\n if (logger.isTraceEnabled()) {\n logger.trace("No @EventListener annotations found on bean class: " + targetType.getName());\n }\n }\n else {\n \/\/ Non-empty set of methods\n ConfigurableApplicationContext context = this.applicationContext;\n Assert.state(context != null, "No ApplicationContext set");\n List<EventListenerFactory> factories = this.eventListenerFactories;\n Assert.state(factories != null, "EventListenerFactory List not initialized");\n for (Method method : annotatedMethods.keySet()) {\n for (EventListenerFactory factory : factories) {\n if (factory.supportsMethod(method)) {\n Method methodToUse = AopUtils.selectInvocableMethod(method, context.getType(beanName));\n ApplicationListener<?> applicationListener =\n factory.createApplicationListener(beanName, targetType, methodToUse);\n if (applicationListener instanceof ApplicationListenerMethodAdapter) {\n ((ApplicationListenerMethodAdapter) applicationListener).init(context, this.evaluator);\n }\n context.addApplicationListener(applicationListener);\n break;\n }\n }\n }\n if (logger.isDebugEnabled()) {\n logger.debug(annotatedMethods.size() + " @EventListener methods processed on bean '" +\n beanName + "': " + annotatedMethods);\n }\n }\n }\n }\n\n \/\/......\n} <\/code><\/pre>\nEventListenerMethodProcessor\u5b9e\u73b0\u4e86SmartInitializingSingleton\u63a5\u53e3\uff0c\u5176afterSingletonsInstantiated\u65b9\u6cd5\u5148\u786e\u5b9atype\uff0c\u7136\u540e\u6267\u884cprocessBean\uff0c\u8be5\u65b9\u6cd5\u4f1a\u5148\u6536\u96c6annotatedMethods\uff0c\u7136\u540e\u904d\u5386\u8be5\u65b9\u6cd5\uff0c\u5728\u904d\u5386factories\u9488\u5bf9\u652f\u6301\u8be5\u65b9\u6cd5\u7684factory\u6267\u884ccreateApplicationListener\uff0c\u6dfb\u52a0\u5230context\u4e2d<\/p><\/blockquote>\n
\u5c0f\u7ed3<\/h2>\n
TransactionalEventListener\u662fEventListener\u7684\u4e8b\u52a1\u611f\u77e5\u7248\u672c\uff0c\u9ed8\u8ba4\u7684\u662fTransactionPhase\u662fAFTER_COMMIT\uff0cTransactionSynchronizationEventAdapter\u53ea\u662f\u8986\u76d6\u4e86beforeCommit\u53caafterCompletion\u4e24\u4e2a\u65b9\u6cd5\uff0c\u5728afterCompletion\u65b9\u6cd5\u4e2d\u6839\u636estatus\u7684\u503c\u4e0ephase\u7684\u503c\u7684\u5339\u914d\u5173\u7cfb\u51b3\u5b9a\u662f\u5426\u6267\u884cprocessEvent\uff0c\u56e0\u800c\u8fd9\u91cc\u629b\u51fa\u7684\u5f02\u5e38\u4f1a\u88ab\u6355\u83b7\u5e76log\u4e0b\u6765<\/p>\n
doc<\/h2>\n