java 如何在 JPA 2.0 中自动检测实体
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How to auto detect entities in JPA 2.0
提问by LuckyLuke
I am pretty sure that I used some sort of auto detection of beans annotated with @Entity in JPA 2.0 in the past but I am not able to find out how. How do you do that instead of listing each bean in a classXML element in the persistence.xml?
我很确定我过去在 JPA 2.0 中使用了某种用 @Entity 注释的 bean 的某种自动检测，但我不知道如何。您如何做到这一点而不是class在persistence.xml的XML 元素中列出每个bean ？
采纳答案by zagyi
Since Spring 3.1, you also have the option to forget persistence.xmlaltogether, and configure your EntityManagerFactoryusing the packagesToScanproperty, similar to this:
从 Spring 3.1 开始，您还可以选择完全忘记 persistence.xml，并配置您EntityManagerFactory使用的packagesToScan属性，类似于：
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
p:dataSource-ref="dataSource"
p:packagesToScan="${jpa.entity.packages}">
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
p:showSql="${hibernate.show_sql}"/>
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
</props>
</property>
</bean>
回答by Paul Vargas
You need add to the persistence.xmlthe next line:
您需要添加到persistence.xml下一行：
<exclude-unlisted-classes>false</exclude-unlisted-classes>
e.g.
例如
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" ...>
<persistence-unit name="YourPU" ...>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="eclipselink.logging.level" value="ALL"/>
<property name="eclipselink.ddl-generation"
value="drop-and-create-tables"/>
</properties>
</persistence-unit>
</persistence>
回答by Gab
See Pascal Thivent answer here : Do I need <class> elements in persistence.xml?
请参阅此处的 Pascal Thivent 回答：我需要persistence.xml 中的 <class> 元素吗？
you have different way to do it, but JPA itself does not support auto-scan. The simplest and cleanest way to reference your entities IMHO is to package your model in a jar and to reference it with <jar-file>MyModel.jar</jar-file>
你有不同的方法来做到这一点，但 JPA 本身不支持自动扫描。恕我直言，引用您的实体的最简单和最干净的方法是将您的模型打包在一个 jar 中并使用<jar-file>MyModel.jar</jar-file>
