我目前正在 Felix (v4.0.3) 上进行 OSGi 项目。我需要使用 JPA，所以我安装了 Apache Aries JPA 包。我还安装了 OpenJPA，我需要它使用 MySQL Connector Bundle 连接到 MySQL 数据库。不幸的是它不起作用，OpenJPA 说它找不到 MySQL JDBC 类，我无法弄清楚是什么坏了，也许我做错了什么。我将在下面解释我安装的内容以及persistence.xml 文件和我得到的实际异常。
这是我安装的 Apache Aries 包的列表:
然后我安装了这些 Apache Aries JPA 包的依赖项。我从 Springsource 下载了它们:
我还安装了 OpenJPA 及其所有依赖项。我找到了捆绑包 2 到 5 (commons-*) 在 库 的文件夹apache-openjpa-2.2.0 下载的文件夹。我下载了 Serp here因为在 lib 文件夹中找到的 jar 不是 OSGi 包。最后我在 Springsource 中找到了最后两个包(#7 和 #8):
一旦我最终安装了 OpenJPA，我仍然需要 MySQL JDBC 驱动程序包，我也是从 Springsource 存储库及其 commons-logging 依赖项获得的:
现在，安装的包列表变得非常大。我说我安装了 OpenJPA，但这只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 没有将它检测为提供者，并且根据 this blog您必须制作另一个包含您自己的激活器的包，以便 Aries 注意到 EclipseLink。我试过了，但没有用，所以我又改用 OpenJPA 了。
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>
执行我的 DAO 类的以下构造函数时发生错误:
@PersistenceContext(unitName="userManager.model")
private EntityManager em;
private EntityManagerFactory emf;
public UserDAOBean() {
em = emf.createEntityManager();
}
这是我在 OpenJPA 找不到 MySQL 时遇到的错误。当然值得一提的是，URL 和用户名/密码都有效:
<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)
我已经消除了异常(它一直在继续)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:由于垃圾邮件限制，我无法发布指向 Aries、OpenJPA 或 EclipseLink 的链接，抱歉:/
最佳答案
多亏了 Holly Cummins，经过又几个小时的研究，我终于找到了解决问题的方法。我将在下面详细说明，这将是一个 很长回答。
如果您想使用 EclipseLink 使用 Apache Aries(我发现它的安装比 OSGi 的 OpenJPA 简单几个数量级，因为它只包含在 5 个包中)，您将不得不直接从 apache checkout EclipseLink - Aries 适配器，因为它尚未发布。
转到适当的文件夹并执行以下命令以获取它:
svn checkout https://svn.apache.org/repos/asf/aries/trunk/jpa/jpa-container-eclipselink-adapter/
你应该得到一个名为 的文件夹jpa-container-eclipselink-adapter .现在，假设您使用的是 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，您将使用路径在您的 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
您必须与其他包一起部署此包(将其复制到 Felix 的 包 文件夹中)。
这就是 EclipseLink 部分，现在为了让您的持久性真正起作用，您必须将 Blueprint 与 Aries 一起使用。这是的列表全部 您需要从 [http://aries.apache.org/downloads/currentrelease.html](Apache Aries 下载页面)获取的包
下载完 Aries 后，您仍然需要依赖项(从 SpringSource 获取它们)。这些是 SLF4J、Log4J、SLF4J Log4J 绑定(bind)和 javax.transaction 1.1 API 的包。
您还需要来自 EclipseLink 的包(您需要 OSGi 包版本)
http://www.eclipse.org/eclipselink/downloads/
打开 zip 文件并获取以下文件:
最后，假设您想使用 MySQL 数据库，您将需要 MySQL JDBC 驱动程序的包(从 Springsource 下载)
一旦你安装了所有这些包，你需要使用 非 jta 数据源 您将通过 JNDI。这是一个可以根据需要更改的 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" 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>
见 javax.sql.Datasource 在非 jta-data-source 标签中？这就是我们将使用 Blueprint xml 定义的内容。
为此，您首先需要添加 OSGI-INF/蓝图/持久性包中的文件夹(包含 DAO 和实体的文件夹)。这是蓝图 xml 文件所在的默认文件夹，位于此处的任何 xml 文件都将被扫描。完成后，创建 blueprint.xml 文件(名称可以更改)并粘贴(和修改)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。这与我们在 中使用的数据源相同持久性.xml 文件。
然后，我们注入(inject) EntityManagerFactory 在我们的 DAO 中。我们的 DAO 是 com.example.dao.beans.UserDAOBean 类，我们需要将其名称添加到 bean 标签。这个类必须实现一个接口(interface)，我们需要将此接口(interface)添加到 服务标签。现在最后 jpa:unit 标记告诉 Aries 注入(inject)与名为 的持久性单元相关的 EntityManagerFactory用户经理 (与我们在persistence.xml 中使用的名称相同)通过使用UserDAOBean 的第一个构造函数。这是通过使用 index="0"属性完成的。这也意味着你必须在你的 DAO 中有一些像下面这样的代码:
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。以下是可帮助您使用 Blueprint 的更多资源:
可选 : 请注意，如果您使用的是 Felix，添加 javax.transaction 包会导致“使用约束冲突”，因为系统包(包 0)也导出此 API。您必须通过更改 中的以下行来阻止它导出它config.properties :
#org.osgi.framework.system.packages=
您必须在此处输入 的列表全部 上一个包导出的包。不幸的是，没有办法“删除”一个包，你必须重新定义要导出的整个包列表。这是我的，我希望它有帮助(是的，它非常非常长):
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
关于java - OSGi 中的 OpenJPA 找不到 MySQL JDBC 连接器包，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11861414/