META-INF/persistence.xml cannot be opened because it does not exist

问题

I'm creating a basic spring-maven project that should run as a java application (in process, not over a web server).

My application context resides under the resources folder which is in my classpath:

<?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:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:ox="http://www.springframework.org/schema/oxm"
    xsi:schemaLocation="
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
   http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
   http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
   http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-3.1xsd">


<!-- Root Context: defines shared resources visible to all other web components -->

<!-- Context -->
<context:component-scan base-package="me.co.nutrition" />

<!-- Properties -->
<context:property-placeholder
    location="classpath:/nutrition.accumulation.properties" />

<!-- DB -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
</bean>

<bean id="persistenceUnitManager"
    class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
    <property name="defaultPersistenceUnitName" value="nutrition-pu"/>
    <property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml"/>
    <property name="defaultDataSource" ref="dataSource" />
</bean>

<!-- JPA -->
<bean id="entityManager"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="persistenceUnitManager" ref="persistenceUnitManager" />
    <property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
</bean>

<!-- jpaVendorAdapter (works in conjunction with the persistence.xml) -->
<bean id="jpaVendorAdapter"
    class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
    <property name="database" value="${jpa.database}" />
    <property name="showSql" value="${jpa.showSql}" />
    <property name="databasePlatform" value="${jpa.dialect}" />
    <property name="generateDdl" value="${jpa.generateDdl}" />
</bean>

<!-- Transactions -->
<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManager" />
    <property name="dataSource" ref="dataSource" />
</bean>

<bean id="persistenceAnnotation" class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

</beans>

I created a META-INF folder as a source folder and added this folder to my classpath. I created my persistence.xml file under this folder.

Here is my persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence 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"
    version="2.0">

<persistence-unit name="nutrition-pu" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
</persistence-unit>
</persistence>

And as mentioned, it is under META-INF folder which is in my classpath. Here is my .classpath file:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="src" output="target/classes" path="src/main/java"/>
    <classpathentry kind="src" output="target/test-classes" path="src/test/java"/>
    <classpathentry kind="src" path="META-INF"/>
    <classpathentry kind="src" path="resources"/>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>
    <classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"/>
    <classpathentry kind="output" path="target/classes"/>
</classpath>

you can see that the META-INF folder is there. I created a simple main that runs:

public static void main(String[] args) throws Exception {

            ApplicationContext context = new ClassPathXmlApplicationContext("accumulationApplicationContext.xml");

...
}

As I run this, when trying to load the application context I get an exception that says the persistence.xml cannot be found or parsed:

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'persistenceUnitManager' defined in class path resource [accumulationApplicationContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Cannot parse persistence unit from class path resource [META-INF/persistence.xml]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1455)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
    ... 30 more
Caused by: java.lang.IllegalArgumentException: Cannot parse persistence unit from class path resource [META-INF/persistence.xml]
    at org.springframework.orm.jpa.persistenceunit.PersistenceUnitReader.readPersistenceUnitInfos(PersistenceUnitReader.java:141)
    at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.readPersistenceUnitInfos(DefaultPersistenceUnitManager.java:380)
    at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.preparePersistenceUnitInfos(DefaultPersistenceUnitManager.java:341)
    at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.afterPropertiesSet(DefaultPersistenceUnitManager.java:326)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
    ... 37 more
Caused by: java.io.FileNotFoundException: class path resource [META-INF/persistence.xml] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158)
    at org.springframework.orm.jpa.persistenceunit.PersistenceUnitReader.readPersistenceUnitInfos(PersistenceUnitReader.java:129)

I can't understand the problem. I'm quite sure i have the right structure, why can't my persistence.xml load?

Thanks in advance!

UPDATE:

Thanks to Boris I got it working. It a seems that I created the META-INF under the wrong path. This happened since I miss understood something with Eclipse project structure. This is the right structure. I hope this helps someone..

回答1:

Your META-INF folder should be directly under the source folder, not to be the source folder by itself.

See Where do I put META-INF in Eclipse?

update From JPA 2.0 Specification

8.2 <...> A persistence unit is defined by a persistence.xml file. The jar file or directory whose META-INF directory contains the persistence.xml file is termed the root of the persistence unit. In Java EE environments, the root of a persistence unit must be one of the following:

an EJB-JAR file

the WEB-INF/classes directory of a WAR file

a jar file in the WEB-INF/lib directory of a WAR file

a jar file in the EAR library directory

an application client jar file

8.2.1 <...> A persistence.xml file defines a persistence unit. The persistence.xml file is located in the META-INF directory of the root of the persistence unit.

So it makes no difference how you configure your project, it's only the resulting jar that matters. If you're using maven, a common practice is to use src/main/resources folder for META-INF.

来源：https://stackoverflow.com/questions/12191914/meta-inf-persistence-xml-cannot-be-opened-because-it-does-not-exist

标签

Spring

classpath

persistence.xml

applicationcontext