java 如何在 EJB 中提交事务？
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how to commit a transaction in EJB?
提问by Muhammad Hewedy
I have the following scenario,
我有以下场景，
public void someEjbMethod1()
{
for (int i=0; i=10; i++)
{
em.merge(arr[i]);
em.flush();
}
}
I need to merge each object of (arr[i]) separately. as the above code will commit all the arr[i]instances at the end of the function.
我需要分别合并 ( arr[i]) 的每个对象。因为上面的代码将arr[i]在函数末尾提交所有实例。
I am thinking to do the following:
我正在考虑执行以下操作：
public void someEjbMethod1()
{
for (int i=0; i=10; i++)
{
saveObj(arr[i]);
}
}
// should I use a transaction attribute here??
public void saveObj(SomeObject obj)
{
em.merge(arr[i]);
em.flush();
}
回答by Vineet Reynolds
If you want container managed transactions, you may use the @TransactionAttribute with the value TransactionAttributeType.REQUIRES_NEWto annotate the saveObjmethod as:
如果你想要容器管理的事务，你可以使用@TransactionAttribute 和值为 TransactionAttributeType.REQUIRES_NEW来注释该saveObj方法：
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void saveObj(SomeObject obj)
{
...
}
This will ensure that a new transaction will be started for every invocation of the saveObjmethod. The existing transaction associated with the someEjbMethodwill be suspended before every invocation of the saveObjmethod. Every transaction started for the saveObjmethod will be committed on return, and hence every entity will be updated in the database in it's own transaction.
这将确保每次调用该saveObj方法都会启动一个新事务。与 关联的现有事务someEjbMethod将在每次调用该saveObj方法之前暂停。为该saveObj方法启动的每个事务都将在返回时提交，因此每个实体都将在其自己的事务中的数据库中更新。
