Springboot 在事务提交后执行任务的使用方案

摘要

主要介绍了在事务注解中的代码块中，需要事务提交后发起mq请求或者其他异步的操作使用的方式。

原理

是在spring的事务提交后再执行的代码，源码如下

执行源码

• 类AbstractPlatformTransactionManager中的processCommit方法

private void processCommit(DefaultTransactionStatus status) throws TransactionException {
   try {
      boolean beforeCompletionInvoked = false;

      try {
         boolean unexpectedRollback = false;
         prepareForCommit(status);
         triggerBeforeCommit(status);
         triggerBeforeCompletion(status);
         beforeCompletionInvoked = true;

         if (status.hasSavepoint()) {
            if (status.isDebug()) {
               logger.debug("Releasing transaction savepoint");
            }
            unexpectedRollback = status.isGlobalRollbackOnly();
            status.releaseHeldSavepoint();
         }
         else if (status.isNewTransaction()) {
            if (status.isDebug()) {
               logger.debug("Initiating transaction commit");
            }
            unexpectedRollback = status.isGlobalRollbackOnly();
            doCommit(status);
         }
         else if (isFailEarlyOnGlobalRollbackOnly()) {
            unexpectedRollback = status.isGlobalRollbackOnly();
         }

         // Throw UnexpectedRollbackException if we have a global rollback-only
         // marker but still didn't get a corresponding exception from commit.
         if (unexpectedRollback) {
            throw new UnexpectedRollbackException(
                  "Transaction silently rolled back because it has been marked as rollback-only");
         }
      }
      catch (UnexpectedRollbackException ex) {
         // can only be caused by doCommit
         triggerAfterCompletion(status, TransactionSynchronization.STATUS_ROLLED_BACK);
         throw ex;
      }
      catch (TransactionException ex) {
         // can only be caused by doCommit
         if (isRollbackOnCommitFailure()) {
            doRollbackOnCommitException(status, ex);
         }
         else {
            triggerAfterCompletion(status, TransactionSynchronization.STATUS_UNKNOWN);
         }
         throw ex;
      }
      catch (RuntimeException | Error ex) {
         if (!beforeCompletionInvoked) {
            triggerBeforeCompletion(status);
         }
         doRollbackOnCommitException(status, ex);
         throw ex;
      }

      // Trigger afterCommit callbacks, with an exception thrown there
      // propagated to callers but the transaction still considered as committed.
      try {
         ### 注意就是改方法调用了我们的执行参数
         triggerAfterCommit(status);
      }
      finally {
         triggerAfterCompletion(status, TransactionSynchronization.STATUS_COMMITTED);
      }

   }
   finally {
      cleanupAfterCompletion(status);
   }
}

事务执行工具类

/**
 * 事务工具类
 */
public class TransactionUtils {

    /**
     * 在事务提交后同步执行
     * @param runnable
     */
    public static void afterCommitSyncExecute(Runnable runnable){
        if (TransactionSynchronizationManager.isSynchronizationActive()) {
            TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
                @Override
                public void afterCommit() {
                    runnable.run();
                }
            });
        } else {
            runnable.run();
        }
    }

    /**
     * 在事务提交后异步执行
     * @param runnable
     */
    public static void afterCommitAsyncExecute(Executor executor, Runnable runnable){
        if (TransactionSynchronizationManager.isSynchronizationActive()) {
            TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
                @Override
                public void afterCommit() {
                    executor.execute(runnable);
                }
            });
        } else {
            executor.execute(runnable);
        }
    }

}

使用案例

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    @Transactional(rollbackFor = Exception.class)
    public void add(User user){
        userMapper.insert(user);
        TransactionUtils.afterCommitSyncExecute(()->{
            System.out.println("事务提交后执行的方法");
        });
    }

}