how we can get JPA EntityManager Flush work

问题

my question is why flush doesn't work :

public void ejbService(){
   Customer c = em.find(Customer.class,1);
   c.setName("newName");
   em.flush();
   //at this point when I query mysql table I can not see "newName"


   thread.sleep(10000);

   c.setName("anotherName");
}

After finishing the method I see "anotherName" in the db also I check it with em.find(Customer.class,1,Lock.None); but still not work

RGDS

回答1:

You're flushing, but you're not committing - or otherwise ending the transaction / session which is likely configured for auto-commit.

Yes, after calling flush(), the DBMS is now aware of your data - but following ACID standards, no other database sessions will see this data until the DBMS is told to commit it.

Without knowing additional details about the architecture behind the rest of your application, etc., you're probably looking to do something like:

em.getTransaction().commit();

来源：https://stackoverflow.com/questions/8863725/how-we-can-get-jpa-entitymanager-flush-work