I need two or more than two connections in my web application using jpa
To use different data sources, add multiple persistence units (say, source-1 and source-2 in persistence.xml and create multiple EntityManagerFactoryes by name):
EntityManagerFactory emf1 = Persistence.createEntityManagerFactory("source-1");
EntityManagerFactory emf2 = Persistence.createEntityManagerFactory("source-2");
or, if you're working on Spring or Java EE application server, inject them by name also:
#PersistenceUnit(name = "source-1")
EntityManagerFactory emf1;
#PersistenceContext(unitName = "source-2") // as an option
EntityManager em2;
persistence.xml will thus look like the following:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="source-1" transaction-type="RESOURCE_LOCAL">
<properties>
<!-- source-1 properties here -->
</properties>
</persistence-unit>
<persistence-unit name="source-2" transaction-type="RESOURCE_LOCAL">
<properties>
<!-- source-2 properties here -->
</properties>
</persistence-unit>
</persistence>
Example of how to configure persistence unit, create EntityManager to manage entities and execute queries can be found here.
For single datasource jpa will use multiple connections internally.So you don't need to do anything.
Related
My application is running perfectly fine in JBoss AS 5.1.0. My goal is to migrate it to Wildfly 10.
Below is my persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
<persistence-unit name="ApplicationPersistenceUnit">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:/MySQL_DS</jta-data-source>
<jar-file>application_db_interface.jar</jar-file>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="jboss.entity.manager.jndi.name" value="java:/ApplicationPersistenceUnit"/>
<property name="jboss.entity.manager.factory.jndi.name" value="java:/ApplicationPersistenceUnitFactory"/>
</properties>
</persistence-unit>
</persistence>
Below is my transaction manager class;
public class TransactionManager implements TransactionManagerI {
#PersistenceContext(unitName="ApplicationPersistenceUnit")
private EntityManager em;
...
}
I also try to use lookup but it still returns null;
public Session getSession() throws DAOException {
..
em = (EntityManager) new InitialContext().lookup("java:/ApplicationPersistenceUnit");
..
}
Below is the project schema;
->application.ear
->application.ear/application.war
->application.ear/db.jar
->application.ear/db.jar/META-INF/persistence.xml
I looked into other solutions and try one by one but couldn't figure out mine yet. I can provide more info if you need.
UPDATE: I check JNDI view from wildfly admin console. I don't see ApplicationPersistenceUnit there. It looks like server doesn't bind my persistence.xml file. I am now trying to figure out this problem.
I would like to get my DataSource properties, like user name or url.
This is my persistence.xml:
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="defaulttransaction-type="JTA">
<jta-data-source>MyDataSource</jta-data-source>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
</persistence-unit>
</persistence>
Inside GlassFish 4.1, I have the required JDBC Resource and JDBC ConnectionPool, respectively MyDataSource and MyDataSourceCP.
If this is useful, MyDataSource is a javax.sql.ConnectionPoolDataSource and MyDataSourceCP is a oracle.jdbc.pool.OracleConnectionPoolDataSource.
MyDataSourceCP is configured with some parameters like URL, user name and password.
I would like to extract those properties from Java.
So far, I have tried the following:
How to get jpa datasource properties from Entity Manager
How to retrieve the datasource used by a persistence unit programmatically
JPA - Is there a way/method to retrieve Persistence Unit information
But with no results.
As #Stoffelchen (in (1)), I would like something like
someObject.someMethod( ).getProperties( )
// or
someObject.someMethod( ).getProperties( "username" )
// or
someObject.someMethod( ).getUserName( )
Is there a way to achieve this?
I am using Hibernate 4.3.
Thanks in advance
I have created a Hibernate / JPA project and I'd like to create entities from tables.
While the tool works like a charm selecting a pure Hibernate configuration, in the JPA mode it does not work, claiming the absence of the persistence unit
As shown in the following photo, the persistence unit is located in the folder /src/main/resources/META-INF
This is the code of persistence.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="socialsports" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistenceProvider</provider>
<jta-data-source>jdbc/LiveDataSource</jta-data-source>
</persistence-unit>
</persistence>
This is the result of my attempt to run Hibernate tools to generate entities:
Since it only doesn't work in JPA mode, the use of the deprecated org.hibernate.ejb.HibernatePersistenceProvider could be a problem. Try org.hibernate.jpa.HibernatePersistenceProvider instead.
I'm getting the error "Class "test2" is mapped, but is not included in any" in eclipse, however the class is included in persistence xml.
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="test1">
<class>com.test.domains.test1</class>
<properties>
<!-- properties for schema1 here -->
</properties>
</persistence-unit>
<persistence-unit name="test2">
<class>com.test.test2</class>
<properties>
<!-- properties for schema 2 here -->
</properties>
</persistence-unit>
</persistence>
Why does this error appear. Do I have to configure it different for 2 db schemas?
Eclipse (or more specifically Dali) do have limitation, it does not support two persistence units. That is also told in their pages:
Currently Dali only supports one Persistence Unit and one Persistence
XML file per project. Other configurations can exist in a JPA project,
but the validation and defaults processing may not be correct when
multiple persistence units are used.
What it comes to JPA itself, persistence.xml seems to becorrect. There is no need to add same class to two persistence units.
We created some libraries that all our projects will use, this libraries will provide the basic functionality of all our systems (login, some manage, etc). But the application itself could use another database.
What we did was to create the Persistence.xml with two persist units. And package all the core library entities in a jar called "LN-model.jar" and all of the entities of out test app in "App-model.jar". But for some reason we still obtain the following message.
Could not resolve a persistence unit corresponding to the persistence-context-ref-name [x.x.x.x.listener.InicializadorListener/em] in the scope of the module called [gfdeploy#/Users/zkropotkine/WORK/SeguridadCore/dist/gfdeploy/SeguridadCore-war_war]. Please verify your application.
Here's our Persistence.xml
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="x" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/x</jta-data-source>
<jar-file>App-model.jar</jar-file>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
</properties>
</persistence-unit>
<persistence-unit name="y" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/y</jta-data-source>
<jar-file>LN-model.jar</jar-file>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties/>
</persistence-unit>
By the way we put the Persistence.xml in a jar, that we add to our Enterprise Project (EAR).
The problem is that the JPA does not know which is the persistence unit to use. when you have only one persistence unit this problem does not occur. To fix do the following:
You need to specify a persistence unit : #PersistenceContext(unitName="...") in the Ejb that do not have
You can add the annotations:
#PersistenceUnit(name = "x")
EntityManagerFactory entityManagerFactory;
#PersistenceContext(unitName = "y")
EntityManager entityManager;
Or you can create it manually:
EntityManagerFactory emfA = Persistence.createEntityManagerFactory("x", properties);
EntityManagerFactory emfB = Persistence.createEntityManagerFactory("y", properties);
For more details, please see the following link: https://docs.oracle.com/html/E25034_01/usingmultipledbs.htm
is very useful, to me helped me!