我目前正在Felix(v4.0.3)上的OSGi项目上工作。我需要使用JPA，所以我已经安装了Apache Aries JPA捆绑软件。我还安装了OpenJPA，我需要它使用MySQL Connector Bundle连接到MySQL数据库。不幸的是，它无法正常工作，OpenJPA说它找不到MySQL JDBC类，而且我无法弄清楚发生了什么，也许我做错了什么。我将在下面解释我确切安装的内容以及persistence.xml文件和得到的实际异常。
这是我安装的Apache Aries捆绑软件的列表:
然后，我安装了这些Apache Aries JPA捆绑软件的依赖项。我从Springsource下载了它们:
我还安装了OpenJPA及其所有依赖项。我在下载的 apache-openjpa-2.2.0 文件夹的 lib 文件夹中找到了捆绑 2到5 (公用-*)。我下载了Serp here，因为在lib文件夹中找到的jar不是OSGi捆绑包。最后，我在Springsource中找到了最后两个捆绑包(＃7和＃8):
一旦我最终安装了OpenJPA，我仍然需要MySQL JDBC Driver捆绑包，我也从Springsource存储库中获得了该捆绑包以及它的commons-logging依赖项:
现在，已安装的捆绑软件列表变得越来越大。我说我安装了OpenJPA，但这仅仅是因为我不知道如何在Aries中使用任何其他提供程序。我最初想使用EclipseLink，但显然Apache Aries并未将其检测为提供程序，并且根据this blog，您必须再制作一个包含您自己的激活器的捆绑软件，以便Aries注意到EclipseLink。我尝试过，但是没有用，所以我转而使用OpenJPA。
所以现在我有两个问题:
或者:
这是我使用的persistence.xml文件:
<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" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="userManager.model" transaction-type="RESOURCE_LOCAL">
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
<class>org.project.dao.entity.UserEntity</class>
<properties>
<property name="openjpa.ConnectionDriverName" value="com.mysql.jdbc.Driver" />
<property name="openjpa.ConnectionURL" value="jdbc:mysql://localhost:3306/usermanager?autoReconnect=true" />
<property name="openjpa.ConnectionUserName" value="root" />
<property name="openjpa.ConnectionPassword" value="root" />
</properties>
</persistence-unit>
</persistence>
当执行以下DAO类的构造函数时，将发生错误:
@PersistenceContext(unitName="userManager.model")
private EntityManager em;
private EntityManagerFactory emf;
public UserDAOBean() {
em = emf.createEntityManager();
}
这是我在使用OpenJPA找不到MySQL时遇到的错误。当然，值得一提的是，URL和用户名/密码都可以使用:
<openjpa-2.2.0-r422266:1244990 nonfatal general error> org.apache.openjpa.persistence.PersistenceException: There were errors initializing your configuration: <openjpa-2.2.0-r422266:1244990 fatal user error> org.apache.openjpa.util.UserException: A connection could not be obtained for driver class "com.mysql.jdbc.Driver" and URL "jdbc:mysql://localhost:3306/usermanager?autoReconnect=true". You may have specified an invalid URL.
at org.apache.openjpa.jdbc.schema.DataSourceFactory.newConnectException(DataSourceFactory.java:255)
at org.apache.openjpa.jdbc.schema.DataSourceFactory.newDataSource(DataSourceFactory.java:123)
at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.createConnectionFactory(JDBCConfigurationImpl.java:844)
at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:732)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:295)
at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1671)
at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:646)
at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:203)
at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:156)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:227)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:154)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:60)
at org.apache.aries.jpa.container.impl.CountingEntityManagerFactory.createEntityManager(CountingEntityManagerFactory.java:64)
at javax.persistence.EntityManagerFactory$$Proxy.createEntityManager(Unknown Source)
我已经切断了异常(它一直持续不断)直到这一点:
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver not found by org.apache.openjpa [12]
at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1460)
at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringImpl.java:72)
at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1843)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.apache.openjpa.jdbc.schema.DataSourceFactory.newDataSource(DataSourceFactory.java:85)
... 108 more
PS:由于垃圾邮件的限制，我无法发布指向Aries，OpenJPA或EclipseLink的链接，很抱歉://
最佳答案
多亏了Holly Cummins，经过数小时的研究，我才能够找到解决问题的方法。我将在下面详细说明，这将是一个很长的答案。
如果您想将 EclipseLink 与Apache Aries一起使用(由于OSGi仅包含在5个软件包中，我发现它的安装数量比OpenJPA更简单)，您将不得不直接从apap checkout EclipseLink-Aries适配器，因为它具有尚未发布。
转到适当的文件夹并执行以下命令来获取它:
svn checkout https://svn.apache.org/repos/asf/aries/trunk/jpa/jpa-container-eclipselink-adapter/
您应该获得一个名为的文件夹jpa-container-eclipselink-adapter 。现在，假设您正在使用Linux并安装了Maven，请运行以下命令:
cd jpa-container-eclipselink-adapter
mvn clean install
一旦Maven成功编译了适配器的源代码，您将使用以下路径在Maven存储库中找到它
<maven-repo>/org/apache/aries/jpa/org.apache.aries.jpa.eclipselink.adapter/0.3.1-SNAPSHOT/org.apache.aries.jpa.eclipselink.adapter-0.3.1-SNAPSHOT.jar
您必须与其他捆绑软件一起部署此捆绑软件(将其复制到Felix的捆绑软件文件夹中)。
因此，这是针对EclipseLink的部分，现在为了使持久性真正起作用，您必须将Blueprint与Aries结合使用。这是列表，所有您需要从[http://aries.apache.org/downloads/currentrelease.html](Apache Aries下载页面)中获得的捆绑软件。
一旦下载完白羊座，您仍然需要依赖项(从SpringSource获得它们)。这些是SLF4J，Log4J，SLF4J Log4J Binding和javax.transaction 1.1 API的捆绑包。
您还需要来自EclipseLink的捆绑软件(您需要OSGi捆绑软件版本)
http://www.eclipse.org/eclipselink/downloads/
打开zip并获取以下文件:
最后，假设您要使用MySQL数据库，则需要MySQL JDBC驱动程序的捆绑包(从Springsource下载)
一旦安装了所有这些捆绑包，就需要使用将通过JNDI获得的非jta数据源。这是一个persistence.xml文件，您可以根据需要进行更改:
<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" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="userManager" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<non-jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=jdbc/userManagerDS)</non-jta-data-source>
<class>com.example.dao.entity.UserEntity</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<!-- EclipseLink should create the database schema automatically -->
<!-- <property name="eclipselink.ddl-generation" value="create-tables" />
<property name="eclipselink.ddl-generation.output-mode" value="database" /> -->
</properties>
</persistence-unit>
</persistence>
请参见non-jta-data-source标签中的 javax.sql.Datasource 吗？这就是我们将使用Blueprint xml定义的内容。
为此，您首先需要在持久性捆绑包(其中包含DAO和实体)中添加 OSGI-INF/blueprint/文件夹。这是蓝图xml文件所在的默认文件夹，将扫描位于此处的任何xml文件。完成后，创建 blueprint.xml 文件(名称可以更改)并粘贴(并修改)以下代码:
<bean id="dataSource" class="com.mysql.jdbc.jdbc2.optional.MysqlDataSource">
<property name="url" value="jdbc:mysql://localhost:3306/usermanager?autoReconnect=true" />
<property name="user" value="root" />
<property name="password" value="root" />
</bean>
<service id="MySQLDataSource" interface="javax.sql.DataSource" ref="dataSource">
<service-properties>
<entry key="osgi.jndi.service.name" value="jdbc/userManagerDS" />
</service-properties>
</service>
<service id="userDAOService" interface="com.example.dao.remote.UserDAORemote">
<bean class="com.example.dao.beans.UserDAOBean">
<jpa:unit index="0" unitname="userManager" />
</bean>
</service>
</blueprint>
在这里，我们正在做两件事。首先，我们告诉Aries创建 userManagerDS 数据源，并使用JDBC驱动程序，URL，用户和密码对其进行配置。这是我们在 persistence.xml 文件中使用的数据源。
然后，我们在DAO中注入(inject) EntityManagerFactory 。我们的DAO是 com.example.dao.beans.UserDAOBean 类，我们需要将其名称添加到 bean 标记中。此类必须实现一个接口(interface)，我们需要将此接口(interface)添加到服务标记中。现在，最后一个 jpa:unit 标记告诉Aries通过使用UserDAOBean的第一个构造函数注入(inject)与名为 userManager (与persistence.xml中使用的名称相同)的持久性单元相关的EntityManagerFactory。这是通过使用index =“0”属性完成的。这也意味着您必须在DAO中具有类似以下代码的代码:
private EntityManager em;
private EntityManagerFactory emf;
public UserDAOBean(EntityManagerFactory emf) {
this.emf = emf;
this.em = emf.createEntityManager();
}
也可以使用setter注入(inject)EMF。这里有更多资源可以帮助您使用Blueprint:
可选:请注意，如果您使用的是Felix，则添加javax.transaction捆绑包将导致“使用约束冲突”，因为系统捆绑包(捆绑包0)也会导出此API。您必须通过更改 config.properties 中的以下行来阻止其导出:
#org.osgi.framework.system.packages=
您必须在列表中放入所有以前的捆绑包导出的软件包。不幸的是，没有办法“删除”软件包，您必须重新定义要导出的软件包的整个列表。这是我的，希望对您有所帮助(是的，非常非常长):
org.osgi.framework.system.packages=org.osgi.framework;version=1.6.0, org.osgi.framework.launch;version=1.0.0, org.osgi.framework.wiring;version=1.0.0, org.osgi.framework.startlevel;version=1.0.0, org.osgi.framework.hooks.bundle;version=1.0.0, org.osgi.framework.hooks.resolver;version=1.0.0, org.osgi.framework.hooks.service;version=1.1.0, org.osgi.framework.hooks.weaving;version=1.0.0, org.osgi.service.packageadmin;version=1.2.0, org.osgi.service.startlevel;version=1.1.0, org.osgi.service.url;version=1.0.0, org.osgi.util.tracker;version=1.5.0, javax.accessibility;version=0.0.0.1_006_JavaSE, javax.activation;version=0.0.0.1_006_JavaSE, javax.activity;version=0.0.0.1_006_JavaSE, javax.annotation.processing;version=0.0.0.1_006_JavaSE, javax.annotation;version=0.0.0.1_006_JavaSE, javax.crypto.interfaces;version=0.0.0.1_006_JavaSE, javax.crypto.spec;version=0.0.0.1_006_JavaSE, javax.crypto;version=0.0.0.1_006_JavaSE, javax.imageio.event;version=0.0.0.1_006_JavaSE, javax.imageio.metadata;version=0.0.0.1_006_JavaSE, javax.imageio.plugins.bmp;version=0.0.0.1_006_JavaSE, javax.imageio.plugins.jpeg;version=0.0.0.1_006_JavaSE, javax.imageio.spi;version=0.0.0.1_006_JavaSE, javax.imageio.stream;version=0.0.0.1_006_JavaSE, javax.imageio;version=0.0.0.1_006_JavaSE, javax.jws.soap;version=0.0.0.1_006_JavaSE, javax.jws;version=0.0.0.1_006_JavaSE, javax.lang.model.element;version=0.0.0.1_006_JavaSE, javax.lang.model.type;version=0.0.0.1_006_JavaSE, javax.lang.model.util;version=0.0.0.1_006_JavaSE, javax.lang.model;version=0.0.0.1_006_JavaSE, javax.management.loading;version=0.0.0.1_006_JavaSE, javax.management.modelmbean;version=0.0.0.1_006_JavaSE, javax.management.monitor;version=0.0.0.1_006_JavaSE, javax.management.openmbean;version=0.0.0.1_006_JavaSE, javax.management.relation;version=0.0.0.1_006_JavaSE, javax.management.remote.rmi;version=0.0.0.1_006_JavaSE, javax.management.remote;version=0.0.0.1_006_JavaSE, javax.management.timer;version=0.0.0.1_006_JavaSE, javax.management;version=0.0.0.1_006_JavaSE, javax.naming.directory;version=0.0.0.1_006_JavaSE, javax.naming.event;version=0.0.0.1_006_JavaSE, javax.naming.ldap;version=0.0.0.1_006_JavaSE, javax.naming.spi;version=0.0.0.1_006_JavaSE, javax.naming;version=0.0.0.1_006_JavaSE, javax.net.ssl;version=0.0.0.1_006_JavaSE, javax.net;version=0.0.0.1_006_JavaSE, javax.print.attribute.standard;version=0.0.0.1_006_JavaSE, javax.print.attribute;version=0.0.0.1_006_JavaSE, javax.print.event;version=0.0.0.1_006_JavaSE, javax.print;version=0.0.0.1_006_JavaSE, javax.rmi.CORBA;version=0.0.0.1_006_JavaSE, javax.rmi.ssl;version=0.0.0.1_006_JavaSE, javax.rmi;version=0.0.0.1_006_JavaSE, javax.script;version=0.0.0.1_006_JavaSE, javax.security.auth.callback;version=0.0.0.1_006_JavaSE, javax.security.auth.kerberos;version=0.0.0.1_006_JavaSE, javax.security.auth.login;version=0.0.0.1_006_JavaSE, javax.security.auth.spi;version=0.0.0.1_006_JavaSE, javax.security.auth.x500;version=0.0.0.1_006_JavaSE, javax.security.auth;version=0.0.0.1_006_JavaSE, javax.security.cert;version=0.0.0.1_006_JavaSE, javax.security.sasl;version=0.0.0.1_006_JavaSE, javax.sound.midi.spi;version=0.0.0.1_006_JavaSE, javax.sound.midi;version=0.0.0.1_006_JavaSE, javax.sound.sampled.spi;version=0.0.0.1_006_JavaSE, javax.sound.sampled;version=0.0.0.1_006_JavaSE, javax.sql.rowset.serial;version=0.0.0.1_006_JavaSE, javax.sql.rowset.spi;version=0.0.0.1_006_JavaSE, javax.sql.rowset;version=0.0.0.1_006_JavaSE, javax.sql;version=0.0.0.1_006_JavaSE, javax.swing.border;version=0.0.0.1_006_JavaSE, javax.swing.colorchooser;version=0.0.0.1_006_JavaSE, javax.swing.event;version=0.0.0.1_006_JavaSE, javax.swing.filechooser;version=0.0.0.1_006_JavaSE, javax.swing.plaf.basic;version=0.0.0.1_006_JavaSE, javax.swing.plaf.metal;version=0.0.0.1_006_JavaSE, javax.swing.plaf.multi;version=0.0.0.1_006_JavaSE, javax.swing.plaf.synth;version=0.0.0.1_006_JavaSE, javax.swing.plaf;version=0.0.0.1_006_JavaSE, javax.swing.table;version=0.0.0.1_006_JavaSE, javax.swing.text.html.parser;version=0.0.0.1_006_JavaSE, javax.swing.text.html;version=0.0.0.1_006_JavaSE, javax.swing.text.rtf;version=0.0.0.1_006_JavaSE, javax.swing.text;version=0.0.0.1_006_JavaSE, javax.swing.tree;version=0.0.0.1_006_JavaSE, javax.swing.undo;version=0.0.0.1_006_JavaSE, javax.swing;version=0.0.0.1_006_JavaSE, javax.tools;version=0.0.0.1_006_JavaSE, javax.transaction.xa;version=0.0.0.1_006_JavaSE, javax.transaction;version=0.0.0.1_006_JavaSE, javax.xml.bind.annotation.adapters;version=0.0.0.1_006_JavaSE, javax.xml.bind.annotation;version=0.0.0.1_006_JavaSE, javax.xml.bind.attachment;version=0.0.0.1_006_JavaSE, javax.xml.bind.helpers;version=0.0.0.1_006_JavaSE, javax.xml.bind.util;version=0.0.0.1_006_JavaSE, javax.xml.bind;version=0.0.0.1_006_JavaSE, javax.xml.crypto.dom;version=0.0.0.1_006_JavaSE, javax.xml.crypto.dsig.dom;version=0.0.0.1_006_JavaSE, javax.xml.crypto.dsig.keyinfo;version=0.0.0.1_006_JavaSE, javax.xml.crypto.dsig.spec;version=0.0.0.1_006_JavaSE, javax.xml.crypto.dsig;version=0.0.0.1_006_JavaSE, javax.xml.crypto;version=0.0.0.1_006_JavaSE, javax.xml.datatype;version=0.0.0.1_006_JavaSE, javax.xml.namespace;version=0.0.0.1_006_JavaSE, javax.xml.parsers;version=0.0.0.1_006_JavaSE, javax.xml.soap;version=0.0.0.1_006_JavaSE, javax.xml.stream.events;version=0.0.0.1_006_JavaSE, javax.xml.stream.util;version=0.0.0.1_006_JavaSE, javax.xml.stream;version=0.0.0.1_006_JavaSE, javax.xml.transform.dom;version=0.0.0.1_006_JavaSE, javax.xml.transform.sax;version=0.0.0.1_006_JavaSE, javax.xml.transform.stax;version=0.0.0.1_006_JavaSE, javax.xml.transform.stream;version=0.0.0.1_006_JavaSE, javax.xml.transform;version=0.0.0.1_006_JavaSE, javax.xml.validation;version=0.0.0.1_006_JavaSE, javax.xml.ws.handler.soap;version=0.0.0.1_006_JavaSE, javax.xml.ws.handler;version=0.0.0.1_006_JavaSE, javax.xml.ws.http;version=0.0.0.1_006_JavaSE, javax.xml.ws.soap;version=0.0.0.1_006_JavaSE, javax.xml.ws.spi;version=0.0.0.1_006_JavaSE, javax.xml.ws.wsaddressing;version=0.0.0.1_006_JavaSE, javax.xml.ws;version=0.0.0.1_006_JavaSE, javax.xml.xpath;version=0.0.0.1_006_JavaSE, javax.xml;version=0.0.0.1_006_JavaSE, org.ietf.jgss;version=0.0.0.1_006_JavaSE, org.omg.CORBA.DynAnyPackage;version=0.0.0.1_006_JavaSE, org.omg.CORBA.ORBPackage;version=0.0.0.1_006_JavaSE, org.omg.CORBA.TypeCodePackage;version=0.0.0.1_006_JavaSE, org.omg.CORBA.portable;version=0.0.0.1_006_JavaSE, org.omg.CORBA;version=0.0.0.1_006_JavaSE, org.omg.CORBA_2_3.portable;version=0.0.0.1_006_JavaSE, org.omg.CORBA_2_3;version=0.0.0.1_006_JavaSE, org.omg.CosNaming.NamingContextExtPackage;version=0.0.0.1_006_JavaSE, org.omg.CosNaming.NamingContextPackage;version=0.0.0.1_006_JavaSE, org.omg.CosNaming;version=0.0.0.1_006_JavaSE, org.omg.Dynamic;version=0.0.0.1_006_JavaSE, org.omg.DynamicAny.DynAnyFactoryPackage;version=0.0.0.1_006_JavaSE, org.omg.DynamicAny.DynAnyPackage;version=0.0.0.1_006_JavaSE, org.omg.DynamicAny;version=0.0.0.1_006_JavaSE, org.omg.IOP.CodecFactoryPackage;version=0.0.0.1_006_JavaSE, org.omg.IOP.CodecPackage;version=0.0.0.1_006_JavaSE, org.omg.IOP;version=0.0.0.1_006_JavaSE, org.omg.Messaging;version=0.0.0.1_006_JavaSE, org.omg.PortableInterceptor.ORBInitInfoPackage;version=0.0.0.1_006_JavaSE, org.omg.PortableInterceptor;version=0.0.0.1_006_JavaSE, org.omg.PortableServer.CurrentPackage;version=0.0.0.1_006_JavaSE, org.omg.PortableServer.POAManagerPackage;version=0.0.0.1_006_JavaSE, org.omg.PortableServer.POAPackage;version=0.0.0.1_006_JavaSE, org.omg.PortableServer.ServantLocatorPackage;version=0.0.0.1_006_JavaSE, org.omg.PortableServer.portable;version=0.0.0.1_006_JavaSE, org.omg.PortableServer;version=0.0.0.1_006_JavaSE, org.omg.SendingContext;version=0.0.0.1_006_JavaSE, org.omg.stub.java.rmi;version=0.0.0.1_006_JavaSE, org.w3c.dom.bootstrap;version=0.0.0.1_006_JavaSE, org.w3c.dom.events;version=0.0.0.1_006_JavaSE, org.w3c.dom.ls;version=0.0.0.1_006_JavaSE, org.w3c.dom;version=0.0.0.1_006_JavaSE, org.xml.sax.ext;version=0.0.0.1_006_JavaSE, org.xml.sax.helpers;version=0.0.0.1_006_JavaSE, org.xml.sax;version=0.0.0.1_006_JavaSE