How to use spring transaction in multithread

问题:

I have a method as below:

ClassA.java
@Transactional
public void methodA(){        
    ExecutorService executorService = Executors.newFixedThreadPool(4);
    executorService.execute(new Runnable() {
        public void run() {
            classB.methodB();
        }
});
}
ClassB.java
@Transactional
public void methodB(){
    updateDB();
}

Can the methodB work well? Per my understanding, methodB will attach the transaction of methodA, what if methodA exits before methodB? I guess only methodA can be commited by the transaction. But methodB will not commit because the transaction commited before.

Can I use @Transactional(propagation = Propagation.REQUIRES_NEW) for methodB. This can let methodB have a new transaction. But according to spring doc, the transcation of methodA will suspend when it invoke methodB. I feel very confuse here.

Can anyone help me on this issue? Thanks in advance.

回答1:

No, methodB() will not be executed in the same transaction as methodA(). Spring's @Transactional only works on a single thread - it creates a session when a thread first enteres a method with @Transactional (or a method in a class with @Transactional), and then commits it when it leaves that method.

In your example, the transaction will end after you schedule the job in the thread pool. methodB() will have it's own transaction.