使用JPA保留第三方对象 [英] Persisting 3rd party objects with JPA
问题描述
在我目前的项目中,我使用的是没有JPA注释的第三方库。
In my current project I am using a 3rd party library which has no JPA annotations.
如何使用JPA和外部映射来保存来自该库的对象?
How can I persist objects from that library using JPA and external mappings?
推荐答案
- 创建
META-INF / orm.xml
- 关注(阅读)
.xsd
- Create
META-INF/orm.xml
- Follow (read) the
.xsd
您不必手动映射每列 - 只需要一些细节(即集合和ID)。假定所有字段都是列(如果映射了类)。如果没有集合,这样的东西就足够了:
You don't have to manually map each column - only some specifics (i.e. collections and the id) are required. All fields are assumed to be columns (if the class is mapped). If there are no collections, something like this suffices:
<?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
http://java.sun.com/xml/ns/persistence/orm_1_0.xsd"
version="1.0">
<description>External entities from library X</description>
<package>com.external.library</package>
<entity class="SomeClassName">
<id>..</id>
</entity>
<entity class="AnotherClassName">
<id>..</id>
</entity>
</entity-mapping>
请注意,当指定< package>
时您不需要完全限定名称。
Note that when specifying <package>
you don't need fully-qualified names.
如果您想要一个名称与 orm.xml不同的文件
,在 persistence.xml
中通过以下方式指定:
In case you want a file named differently than orm.xml
, in your persistence.xml
specify it via:
<mapping-file>customMappingFile.xml</mapping-file>
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