休眠注释/ XML解决方法

Question

I am working on a project in hibernate where there is both annotations and xml mapped entities.

Here is the setup, Entity/Class A is annotation based.

Class A

@Id
long id;

I need a collection in class A, that can only be mapped through XML configurations. We cannot mix annotations and xml for a given entity I know.

But can I just create a wrapper class, call it X, and create a corresponding XML mapping for X with the collection xml configuration that I would have put in A? So we'd have:

Class A

@Id
long id;

Object X;

And then also a X.hbm.xml file. Note this file will contain mapping to formulate a collection of a column from say Table B, that is mapped by A's primary key which is a foreign key in B. So I guess it will actually have to reference Table A and B.

Is this workaround going to work or not? Seems like a long shot...

Answer 1

You may try mapping files (I used them to redefine some properties of an "external" entity)

persistence.xml

<persistence-unit name="yourPersistenceUnit" transaction-type="RESOURCE_LOCAL">
  <provider>org.hibernate.ejb.HibernatePersistence</provider>
  <mapping-file>META-INF/orm-custom.xml</mapping-file>

orm-custom.xml

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings
        xmlns="http://java.sun.com/xml/ns/persistence/orm"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
        version="2.0">

    <entity class="your.Entity">
        <attributes>
            <one-to-many name="attributes" fetch="LAZY"/>
            <one-to-many name="answers" fetch="LAZY"/>
        </attributes>
    </entity>
</entity-mappings>