我目前正在使用 OSGi 进行测试。我正在通过 Eclipse 运行它。我想让我的 DAO 层成为 OSGi 解决方案的一部分，但我的第一个绊脚石是这个错误:

Jun 29, 2009 6:12:37 PM org.hibernate.cfg.annotations.Version <clinit>
INFO: Hibernate Annotations 3.3.0.GA
Jun 29, 2009 6:12:37 PM org.hibernate.ejb.Version <clinit>
INFO: Hibernate EntityManager 3.3.0.GA
Jun 29, 2009 6:12:37 PM org.hibernate.ejb.Ejb3Configuration configure
INFO: Could not find any META-INF/persistence.xml file in the classpath

我试过将 persistence.xml 文件放在很多不同的地方，但都无济于事。 对我做错了什么有什么想法吗？

有没有办法手动加载 persistence.xml？

激活器如下所示:

package com.activator;


public class PersistenceActivator implements BundleActivator {

    @Override
    public void start(BundleContext arg0) throws Exception {

        EntityManagerFactory emf = Persistence
                .createEntityManagerFactory("postgres");
        EntityManager em = emf.createEntityManager();

        SimpleDaoImpl dao = new SimpleDaoImpl();
        dao.setEntityManager(em);

    }

    @Override
    public void stop(BundleContext arg0) throws Exception {
        // TODO Auto-generated method stub

    }

}

这是我的目录结构:

alt text http://www.freeimagehosting.net/uploads/7b7b7d2d30.jpg

这是我的Manifest.MF

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Dao Plug-in
Bundle-SymbolicName: Dao
Bundle-Version: 1.0.0
Bundle-RequiredExecutionEnvironment: JavaSE-1.6
Import-Package: org.osgi.framework;version="1.4.0"
Bundle-Activator: com.activator.PersistenceActivator
Export-Package: com.dao.service
Require-Bundle: HibernateBundle;bundle-version="1.0.0"

HibernateBundle 包含所有 Hibernate 和 Persistence Jar。

这是我的Persistence.xml

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

<persistence>

    <!-- Sample persistence using PostgreSQL. See postgres.txt. -->
    <persistence-unit name="postgres" transaction-type="RESOURCE_LOCAL">

        <properties>


            <property name="hibernate.archive.autodetection" value="class" />

            <!--
                Comment out if schema exists & you don't want the tables dropped.
            -->
            <property name="hibernate.hbm2ddl.auto" value="create-drop" /> <!-- drop/create tables @startup, drop tables @shutdown -->


            <!-- Database Connection Settings -->
            <property name="hibernate.connection.autocommit">true</property>
            <property name="hibernate.connection.driver_class" value="org.postgresql.Driver" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
            <property name="hibernate.connection.username" value="postgres" />
            <property name="hibernate.connection.password" value="postgres" />
            <property name="hibernate.connection.url" value="jdbc:postgresql://localhost:5432/test" />

            <!-- Not sure about these...  -->
            <property name="hibernate.max_fetch_depth">16</property>
            <property name="hibernate.jdbc.batch_size">1000</property>
            <property name="hibernate.use_outer_join">true</property>
            <property name="hibernate.default_batch_fetch_size">500</property>

            <!-- Hibernate Query Language (HQL) parser. -->
            <property name="hibernate.query.factory_class">
                org.hibernate.hql.ast.ASTQueryTranslatorFactory</property>

            <!-- Echo all executed SQL to stdout -->
            <property name="hibernate.show_sql">true</property>
            <property name="hibernate.format_sql">false</property>

            <!-- Use c3p0 for the JDBC connection pool -->
            <property name="hibernate.c3p0.min_size">3</property>
            <property name="hibernate.c3p0.max_size">100</property>
            <property name="hibernate.c3p0.max_statements">100</property>

            <property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />

        </properties>
    </persistence-unit>



</persistence>

我在 Manifest 的类路径中尝试过但没有成功的事情:

Bundle-ClassPath: ., META-INF/persistence.xml

Bundle-ClassPath: ., ../META-INF/persistence.xml

Bundle-ClassPath: .,/META-INF/persistence.xml

Bundle-ClassPath: ., ./META-INF/persistence.xml

Bundle-ClassPath: ., META-INF

Bundle-ClassPath: ., ../META-INF

Bundle-ClassPath: .,/META-INF

Bundle-ClassPath: ., ./META-INF

Bundle-ClassPath: ., C:\Workspaces\OSGiJPA\Dao\META-INF\persistence.xml

Bundle-ClassPath: ., C:\Workspaces\OSGiJPA\Dao\META-INF

最佳答案

使用EclipseLink忘记 Hibernate 和其他实现，因为:

• 您将不得不过多地使用类加载器... Thread.currentThread().setContextClassLoader(...)

• 您很想设置 bundle-classpath 属性并手动添加依赖项，而不是安装 jar 包。

• 您将收到provider not found 错误，或者您可能无法找到persistence.xml

经过多次尝试，上述所有努力都可能无法奏效。

但是，使用 EclipseLink 就很容易了，该实现被设计为在 OSGI 环境中开箱即用，并且没有任何类加载问题。

关于java - Persistence.xml 和 OSGi (Equinox)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/1061091/