使用Maven嵌入式Glassfish配置外部数据库

Question

I need to create educational demo of java web-application using EJB.

I want to use maven embedded-glassfish plugin to simplify matter for people who will run this demo (so that they need not manually set up and configure glassfish server).

However, I could not understand how to force embedded-glassfish to use other database rather than temporary apache derby. I use Java Persistence API - and I want users to use permanent database, for example H2, started by my application (it starts all right).

I've tried straightforward idea - to configure what I need by 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="demoData" transaction-type="JTA">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
            <property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:h2:tcp://127.0.0.1:12345/demodb"/>
            <property name="javax.persistence.jdbc.user" value="sa"/>
            <property name="javax.persistence.jdbc.password" value=""/>
            <property name="eclipselink.ddl-generation" value="create-tables"/>
        </properties>
    </persistence-unit>

</persistence>

It is not ignored completely, it is loaded - but my JPA works with default database anyway. What can I do? Can I reconfigure jdbc/__default datasource somehow, or make my persistence file work? Thanks in advance!

Answer 1

In a JavaEE container context it's unusal to configure the JDBC connection directly in the persistence unit. Instead, the JDBC connection is being configured separately as data source, which is being referenced in the persistence unit via the javax.persistence.jtaDataSource property (this gives the container a chance to manage connection pooling etc).

Because the jtaDataSource is not being set, the container "falls back" to the default data source under "jdbc/__default".

My suggestion is that you configure your own datasource that can be referenced in the persistence.xml.