如何通过 database.properties 文件使数据库配置可配置的 persistence.xml 文件
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【中文标题】如何通过 database.properties 文件使数据库配置可配置的 persistence.xml 文件【英文标题】：how to make database configuration configurable of persistance.xml file through database.properties file 【发布时间】：2016-02-28 17:29:49 【问题描述】：我想确认查询“有什么方法可以通过persistance.xml 中的database.properties 进行数据库配置配置”。以下是可能的吗？
我的以下配置工作得很好，
<?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="spring-data-jpa-krishna" transaction-type="RESOURCE_LOCAL">
<class>net.javabeat.springdata.model.Address</class>
<class>net.javabeat.springdata.model.Employee</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/test" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="root" />
<property name="hibernate.show_sql" value="true" />
<property name="eclipselink.logging.level" value="FINE" />
<property name="eclipselink.ddl-generation" value="create-tables" />
</properties>
</persistence-unit>
</persistence>
但是我有很多环境可以部署 Dev、QA、UAT、SAT、SystemTest 等应用程序代码，所以我想进行如下配置 数据库属性：
mysql.jdbc.driver.class=com.mysql.jdbc.Driver
mysql.jdbc.url=jdbc:mysql://localhost:3306/test
mysql.jdbc.username=root
mysql.jdbc.password=root
hibernate.show_sql=true
eclipselink.logging.level=FINE
eclipselink.ddl-generation=create-tables
persistence.xml
<?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="spring-data-jpa-krishna" transaction-type="RESOURCE_LOCAL">
<class>net.javabeat.springdata.model.Address</class>
<class>net.javabeat.springdata.model.Employee</class>
<properties>
<property name="javax.persistence.jdbc.url" value="$mysql.jdbc.url" />
<property name="javax.persistence.jdbc.driver" value="$mysql.jdbc.driver.class" />
<property name="javax.persistence.jdbc.user" value="$mysql.jdbc.username" />
<property name="javax.persistence.jdbc.password" value="$mysql.jdbc.password" />
<property name="hibernate.show_sql" value="$hibernate.show_sql" />
<property name="eclipselink.logging.level" value="$eclipselink.logging.level" />
<property name="eclipselink.ddl-generation" value="eclipselink.ddl-generation" />
</properties>
</persistence-unit>
</persistence>
这将帮助我解决开销问题。但我想知道persistece.xml 将如何加载database.properties 以正确获取占位符？
这个How to externalize properties from JPAs persistence.xml? 链接是通过JNDI 完成的，但我只是想通过database.properties 文件完成。
编辑-1： 是的，我使用的是 spring-Context.xml 文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:util="http://www.springframework.org/schema/util"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- For consider the using of annotations foe defining Spring Bean -->
<context:annotation-config />
<!-- For defining Spring Bean -->
<context:component-scan base-package="net.javabeat.springdata.beans" />
<!-- For bootstrapping the Spring Repository -->
<jpa:repositories base-package="net.javabeat.springdata.repository" />
<!-- Necessary to get the entity manager injected into the factory bean -->
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
<bean id="registrationBean" class="net.javabeat.springdata.beans.RegistrationBean" />
<!-- ======= WAY-1 ========= -->
<!-- ===== Define EclipseLink JPA Vendor Adapter ===== -->
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
<property name="databasePlatform" value="org.eclipse.persistence.platform.database.MySQLPlatform" />
<property name="generateDdl" value="false" />
<property name="showSql" value="true" />
</bean>
<!-- Entity Manager Factory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
=========== Read persistent.xml file from here ===========
<property name="persistenceUnitName" value="spring-data-jpa-krishna" />
<property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
<!-- spring based scanning for entity classes-->
<property name="packagesToScan" value="net.javabeat.springdata.*" />
</bean>
<!-- Transaction Manager -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<!-- Enable Transactional Manner -->
<tx:annotation-driven transaction-manager="transactionManager" />
</beans>
Edit-1：我现在看到以下错误：
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private net.javabeat.springdata.repository.EmployeeRepository net.javabeat.springdata.beans.RegistrationBean.employeeRepository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeRepository': Cannot create inner bean '(inner bean)#5d3c9c43' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5d3c9c43': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [SpringContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: PersistenceProvider [org.eclipse.persistence.jpa.PersistenceProvider@6201c010] did not return an EntityManagerFactory for name 'spring-data-jpa-krishna'
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:561)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
... 13 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeRepository': Cannot create inner bean '(inner bean)#5d3c9c43' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5d3c9c43': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [SpringContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: PersistenceProvider [org.eclipse.persistence.jpa.PersistenceProvider@6201c010] did not return an EntityManagerFactory for name 'spring-data-jpa-krishna'
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:313)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:129)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1475)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1220)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1120)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1044)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:942)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:533)
... 15 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5d3c9c43': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [SpringContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: PersistenceProvider [org.eclipse.persistence.jpa.PersistenceProvider@6201c010] did not return an EntityManagerFactory for name 'spring-data-jpa-krishna'
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:634)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:444)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1117)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1012)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:299)
... 28 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [SpringContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: PersistenceProvider [org.eclipse.persistence.jpa.PersistenceProvider@6201c010] did not return an EntityManagerFactory for name 'spring-data-jpa-krishna'
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1572)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
... 36 more
Caused by: java.lang.IllegalStateException: PersistenceProvider [org.eclipse.persistence.jpa.PersistenceProvider@6201c010] did not return an EntityManagerFactory for name 'spring-data-jpa-krishna'
at org.springframework.orm.jpa.LocalEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalEntityManagerFactoryBean.java:90)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1631)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1568)
... 43 more
我对 pom.xml 文件进行了更改：
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>$java.version</source>
<target>$java.version</target>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<!-- <filters>
<filter>database.properties</filter>
</filters> -->
<resources>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
</build>
persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="spring-data-jpa-krishna" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>net.javabeat.springdata.model.Address</class>
<class>net.javabeat.springdata.model.Employee</class>
<!-- http://docs.oracle.com/cd/E16439_01/doc.1013/e13981/cfgdepds005.htm -->
<properties>
<property name="javax.persistence.jdbc.url" value="$jdbc.mysql.url" />
<property name="javax.persistence.jdbc.driver" value="$jdbc.mysql.driver.class" />
<property name="javax.persistence.jdbc.user" value="$jdbc.mysql.username" />
<property name="javax.persistence.jdbc.password" value="$jdbc.mysql.password" />
<property name="eclipselink.logging.level" value="FINE" />
<property name="eclipselink.ddl-generation" value="create-tables" />
</properties>
</persistence-unit>
</persistence>
【问题讨论】：
如果您使用 Spring，您可以选择不使用persistence.xml 并从database.properties 获取属性来配置LocalContainerEntityManagerFactoryBean。
另外，您同时使用了Eclipse Link 和Hibernate 特定选项，为什么？
Ali - 是的，我正在使用 spring，请参阅下面的更新和 spring-Context.xml 文件。可能是 Hibernate 特定的选项可能不相关且未被使用，以上配置就是证明
你误将我心爱的persistence.xml复制了两次。
【参考方案1】：
当您使用 Spring 时，您可以选择根本不使用 persistence.xml，并通过名为 LocalContainerEntityManagerFactoryBean 的 FactoryBean 配置 EntityManagerFactory。这个answer 可以让您了解如何配置LocalContainerEntityManagerFactoryBean。
如果您坚持使用persistence.xml，您可以在persistence.xml 中添加$... 占位符，并使用Maven 的资源过滤 来填充实际值。使用这种方法，您应该将 Property Values 定义为 Maven 属性，并且您不需要单独的 database.properties。在这种方法中，您应该将属性添加为 maven 属性，如下所示：
<properties>
<mysql.jdbc.driver.class>com.mysql.jdbc.Driver</<mysql.jdbc.driver.class>
<mysql.jdbc.url>jdbc:mysql://localhost:3306/test</mysql.jdbc.url>
<mysql.jdbc.username>root</mysql.jdbc.username>
<mysql.jdbc.password>root</mysql.jdbc.password>
<hibernate.show_sql>true</hibernate.show_sql>
<!-- You've got to be kidding me! -->
<eclipselink.logging.level>FINE</eclipselink.logging.level>
<eclipselink.ddl-generation>create-tables</eclipselink.ddl-generation>
</properties>
然后将这些添加到pom.xml 中的构建部分：
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
</build>
src/main/resources 中资源中具有 $... 语法的每个占位符都将替换为其实际值，即在 pom.xml 的 properties 部分中定义的值。
【讨论】：
阿里 - 非常感谢你，请查看我的更新 Edit-1 您应该将这些properties 添加到您的 pom.xml
你能看一下我来自github.com/test512/spring-data-jpa-krishna的代码吗？它不适合我
我可以修复您的项目，但 imo 最好使用 Spring Boot。它将代表您自动配置大多数这些配置。看看spring boot，相信我，值得！
同意，谢谢，我很快就会全力以赴。目前，请修复此问题。以上是关于如何通过 database.properties 文件使数据库配置可配置的 persistence.xml 文件的主要内容，如果未能解决你的问题，请参考以下文章