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本文次要钻研一下TransactionSynchronization的invokeAfterCompletion
afterCompletion
org/springframework/transaction/support/TransactionSynchronization.java
public interface TransactionSynchronization extends Flushable { /** Completion status in case of proper commit. */ int STATUS_COMMITTED = 0; /** Completion status in case of proper rollback. */ int STATUS_ROLLED_BACK = 1; /** Completion status in case of heuristic mixed completion or system errors. */ int STATUS_UNKNOWN = 2; //...... /** * Invoked after transaction commit. Can perform further operations right * <i>after</i> the main transaction has <i>successfully</i> committed. * <p>Can e.g. commit further operations that are supposed to follow on a successful * commit of the main transaction, like confirmation messages or emails. * <p><b>NOTE:</b> The transaction will have been committed already, but the * transactional resources might still be active and accessible. As a consequence, * any data access code triggered at this point will still "participate" in the * original transaction, allowing to perform some cleanup (with no commit following * anymore!), unless it explicitly declares that it needs to run in a separate * transaction. Hence: <b>Use {@code PROPAGATION_REQUIRES_NEW} for any * transactional operation that is called from here.</b> * @throws RuntimeException in case of errors; will be <b>propagated to the caller</b> * (note: do not throw TransactionException subclasses here!) */ default void afterCommit() { } /** * Invoked after transaction commit/rollback. * Can perform resource cleanup <i>after</i> transaction completion. * <p><b>NOTE:</b> The transaction will have been committed or rolled back already, * but the transactional resources might still be active and accessible. As a * consequence, any data access code triggered at this point will still "participate" * in the original transaction, allowing to perform some cleanup (with no commit * following anymore!), unless it explicitly declares that it needs to run in a * separate transaction. Hence: <b>Use {@code PROPAGATION_REQUIRES_NEW} * for any transactional operation that is called from here.</b> * @param status completion status according to the {@code STATUS_*} constants * @throws RuntimeException in case of errors; will be <b>logged but not propagated</b> * (note: do not throw TransactionException subclasses here!) * @see #STATUS_COMMITTED * @see #STATUS_ROLLED_BACK * @see #STATUS_UNKNOWN * @see #beforeCompletion */ default void afterCompletion(int status) { }}afterCompletion办法有入参status，示意事务完结时候的状态，0示意事务已提交，1示意事务已回滚，2示意事务未知；与afterCommit的一个最重要的区别是afterCompletion的异样会被捕捉，不像afterCommit会抛给调用方
invokeAfterCompletion
org/springframework/transaction/support/TransactionSynchronizationUtils.java
/** * Actually invoke the {@code afterCompletion} methods of the * given Spring TransactionSynchronization objects. * @param synchronizations a List of TransactionSynchronization objects * @param completionStatus the completion status according to the * constants in the TransactionSynchronization interface * @see TransactionSynchronization#afterCompletion(int) * @see TransactionSynchronization#STATUS_COMMITTED * @see TransactionSynchronization#STATUS_ROLLED_BACK * @see TransactionSynchronization#STATUS_UNKNOWN */ public static void invokeAfterCompletion(@Nullable List<TransactionSynchronization> synchronizations, int completionStatus) { if (synchronizations != null) { for (TransactionSynchronization synchronization : synchronizations) { try { synchronization.afterCompletion(completionStatus); } catch (Throwable tsex) { logger.error("TransactionSynchronization.afterCompletion threw exception", tsex); } } } }能够看到TransactionSynchronizationUtils的invokeAfterCompletion办法会遍历synchronizations，挨个执行afterCompletion，留神这里catch了Throwable异样，进行了error级别的log
AbstractPlatformTransactionManager
org/springframework/transaction/support/AbstractPlatformTransactionManager.java
/** * Actually invoke the {@code afterCompletion} methods of the * given Spring TransactionSynchronization objects. * <p>To be called by this abstract manager itself, or by special implementations * of the {@code registerAfterCompletionWithExistingTransaction} callback. * @param synchronizations a List of TransactionSynchronization objects * @param completionStatus the completion status according to the * constants in the TransactionSynchronization interface * @see #registerAfterCompletionWithExistingTransaction(Object, java.util.List) * @see TransactionSynchronization#STATUS_COMMITTED * @see TransactionSynchronization#STATUS_ROLLED_BACK * @see TransactionSynchronization#STATUS_UNKNOWN */ protected final void invokeAfterCompletion(List<TransactionSynchronization> synchronizations, int completionStatus) { TransactionSynchronizationUtils.invokeAfterCompletion(synchronizations, completionStatus); } /** * Trigger {@code afterCompletion} callbacks. * @param status object representing the transaction * @param completionStatus completion status according to TransactionSynchronization constants */ private void triggerAfterCompletion(DefaultTransactionStatus status, int completionStatus) { if (status.isNewSynchronization()) { List<TransactionSynchronization> synchronizations = TransactionSynchronizationManager.getSynchronizations(); TransactionSynchronizationManager.clearSynchronization(); if (!status.hasTransaction() || status.isNewTransaction()) { if (status.isDebug()) { logger.trace("Triggering afterCompletion synchronization"); } // No transaction or new transaction for the current scope -> // invoke the afterCompletion callbacks immediately invokeAfterCompletion(synchronizations, completionStatus); } else if (!synchronizations.isEmpty()) { // Existing transaction that we participate in, controlled outside // of the scope of this Spring transaction manager -> try to register // an afterCompletion callback with the existing (JTA) transaction. registerAfterCompletionWithExistingTransaction(status.getTransaction(), synchronizations); } } }AbstractPlatformTransactionManager的invokeAfterCompletion委托给了TransactionSynchronizationUtils.invokeAfterCompletion；triggerAfterCompletion次要是依据事务状态执行不同逻辑，别离是invokeAfterCompletion与registerAfterCompletionWithExistingTransaction，后者次要是JTA之类的场景，它回传的status是STATUS_UNKNOWN
小结
afterCompletion办法有入参status，示意事务完结时候的状态，0示意事务已提交，1示意事务已回滚，2示意事务未知(个别是JTA相干)；与afterCommit的一个最重要的区别是afterCompletion的异样(Throwable)会被捕捉，不像afterCommit会抛给调用方
doc
- 聊聊spring的TransactionSynchronizationAdapter