How to add multiple entityNamager in one war?

[garyyding]

How to add multiple entityNamager in one war?

I need multiple database connection in one war, how can I do it?

[garyyding]

Any people can give some sugestion?

On one war or web application, it is easy to use one entityMaager to connect one database.But if I want connect multiple database, how I define multiple entityManager, and then injected into my service class?When I define multiple entityManager in components.xml file, it will issue error: found same components. Why?

[swd847]

Declare the two entityManagers in persistence.xml, then declare them in components.xml with different names.

[garyyding]

My code is
<code>
EntityManager em2 =  (EntityManager)getInstance("em2");
EntityManager em1 =  (EntityManager)getInstance("em");
User user = new User("test11","test11","test11");
em1.persist(user);
em2.persist(user);
</code>

But I found it is ok for "em1.persist(user);"
but fail for "em2.persist(user);". When I call it, nothing happened. No database operation from console, no data saved into database.

Please help to give some suggestion. Thanks.


Please refer to detailed configuration
1. in components.xml
<code>
        <transaction:entity-transaction  entity-manager="#{em}" />
        <persistence:entity-manager-factory name="wfwcoredatasource" persistence-unit-name="wfwcoredatasource"/>
        <persistence:managed-persistence-context name="em"
        auto-create="true" entity-manager-factory="#{wfwcoredatasource}" />


        <transaction:entity-transaction name="tt2" entity-manager="#{em2}"/>
        <persistence:entity-manager-factory name="wfwcoredatasource2" persistence-unit-name="wfwcoredatasource2"/>
        <persistence:managed-persistence-context name="em2" 
        auto-create="true" entity-manager-factory="#{wfwcoredatasource2}" />
</code>

2. in persistence.xml
<code>
<persistence-unit name="wfwcoredatasource"
                transaction-type="RESOURCE_LOCAL">  
.....
</persistence-unit>

<persistence-unit name="wfwcoredatasource2"
                transaction-type="RESOURCE_LOCAL">  
.....
</persistence-unit>

</code>

[garyyding]

It seems that I am wrong to set/use the seam transaction.

[garyyding]

If I write the following code, it is ok

em2.getTransaction().begin();
em2.persist(u);
em2.getTransaction().commit();

But I don't want it.

[swd847]

I take it you do not have the option of using JTA transactions rather than RESOURCE_LOCAL?