Question

我正在尝试从几个jar文件加载实体。我设法做的是

配置hibernate

private void configure(File[] moduleFiles)
{
Configuration configuration = new Configuration()
    .setProperty("hibernate.connection.url", getConnectionString())
    .setProperty("hibernate.connection.username", "user")
    .setProperty("hibernate.connection.password", "pass")
    .setProperty("hibernate.connection.driver_class", "org.hsqldb.jdbc.JDBCDriver")
    .setProperty("hibernate.dialect", "org.hibernate.dialect.HSQLDialect")
    .setProperty("hibernate.archive.autodetection", "class,hbm")
    .setProperty("exclude-unlisted-classes", "false")
    .setProperty("hibernate.hbm2ddl.auto", "update");

if (moduleFiles != null) {
    for (File f : moduleFiles) {
        configuration.addJar(f);
    }
}

ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
this.sessionFactory = configuration.buildSessionFactory(serviceRegistry);
}

所以实体应该从moduleFiles数组加载。在日志中我可以看到：

    2015-08-25 20:52:12 INFO  Configuration:837 - HHH000235: Searching for mapping documents in jar: ProgramInfo.jar
    2015-08-25 20:52:12 INFO  Configuration:837 - HHH000235: Searching for mapping documents in jar: SampleModule.jar

外部jar中的实体

@Entity
@Table(name = "PROGRAMINFO_DATA", schema = "PUBLIC", catalog = "PUBLIC")
@NamedQueries({@NamedQuery(name = "PrograminfoDataEntity.findByWindowInfo", query = "FROM PrograminfoDataEntity WHERE PROCESSPATH = :pp AND WINDOWTITLE = :wt AND DAY = :d")})
public class PrograminfoDataEntity implements SVEntity {
    private long id;
    private Date day;
    private String processname;
    private String processpath;
    private String programname;
    private String windowtitle;

    // getters setters etc.
}

persistence.xml（META-INF目录）

<persistence-unit name="ProgramInfoPersistenceUnit">
    <class>com.antara.modules.programinfo.db.model.PrograminfoDataEntity</class>
</persistence-unit>

使用上述实体用法查询

    Session session = openSession();
    Query q = session.getNamedQuery("PrograminfoDataEntity.findByWindowInfo");
    q.setParameter("pp", windowInfo.getProcessPath());
    q.setParameter("wt", windowInfo.getWindowTitle());
    q.setDate("d", date);

    PrograminfoDataEntity result = (PrograminfoDataEntity) q.uniqueResult();
    closeSession(session);

引发了例外：

org.hibernate.MappingException: Named query not known: PrograminfoDataEntity.findByWindowInfo
    at org.hibernate.internal.AbstractSessionImpl.getNamedQuery(AbstractSessionImpl.java:177)
    at org.hibernate.internal.SessionImpl.getNamedQuery(SessionImpl.java:1372)
    at com.antara.modules.programinfo.db.dao.PrograminfoDao.findByWindowInfo(PrograminfoDao.java:26)
    at com.antara.modules.programinfo.ProgramInfoImpl.run(ProgramInfoImpl.java:84)

问题是为什么hibernate没有从jar加载带注释的实体？不仅通过命名查询而且通过实体执行任何其他操作引发异常。使用此实体前没有错误。本地实体已正确加载。

修改

经过一些更改后，我设法通过Hibernate识别实体

DEBUG AnnotationBinder:601 - Binding entity from annotated class: com.antara.modules.programinfo.db.model.PrograminfoDataEntity
DEBUG QueryBinder:93 - Binding named query: PrograminfoDataEntity.findByWindowInfo => FROM PrograminfoDataEntity ....

但是当我尝试使用该实体时，我仍然会遇到异常：

ERROR AssertionFailure:61 - HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): java.lang.ClassNotFoundException: com.antara.modules.programinfo.db.model.PrograminfoDataEntity
ERROR Main:114 - PersistentClass name cannot be converted into a Class
...
Caused by: java.lang.ClassNotFoundException: com.antara.modules.programinfo.db.model.PrograminfoDataEntity

改变是：将配置传递给每个＆＃34;模块＆＃34;这是在jar内部并添加Annotated Class（通过模块我的意思是SPI服务与启动时调用的方法）

@Override
public void configureDB(Configuration configuration) {
    configuration.addAnnotatedClass(PrograminfoDataEntity.class);
}

Answer 1

经过3天的试验，我找到了解决办法：Hibernate使用ContextClassLoader的反射机制来破坏类

Thread.currentThread().getContextClassLoader();

所以我将ContextClassLoader设置为PrograminfoDataEntity的ClassLoader

Thread.currentThread().setContextClassLoader(PrograminfoDataEntity.class.getClassLoader());

它解决了所有NoClassDefFound，ClassCastException和类似错误

Answer 2

根据javadoc and implementation code Hibernate只在Configuration.addJar方法中读取* .hbm.xml

我认为由于JPA规范中的限制，Hibernate不会自动扫描jar文件

我已经在hibernate中对jar进行了自动扫描，扩展了扫描仪并在其上添加了jar。但你应该使用JPA api。类似的东西：

Map<String, Object> map = new HashMap<>();
map.put("hibernate.connection.url", getConnectionString());
map.put("hibernate.connection.username", "user");
map.put("hibernate.connection.password", "pass");
map.put("hibernate.connection.driver_class", "org.hsqldb.jdbc.JDBCDriver");
map.put("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");
map.put("hibernate.archive.autodetection", "class,hbm");
map.put("exclude-unlisted-classes", "false");
map.put("hibernate.hbm2ddl.auto", "update");
//Property to change scanner
map.put("hibernate.ejb.resource_scanner", "me.janario.MyScanner");

EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProgramInfoPersistenceUnit", map);
SessionFactory sessionFactory = ((HibernateEntityManagerFactory) emf).getSessionFactory();

扫描仪就像：

public class MyScanner extends StandardScanner {
    @Override
    public ScanResult scan(PersistenceUnitDescriptor persistenceUnit, ScanOptions scanOptions) {
        try {
            persistenceUnit.getJarFileUrls()
                    .add(new URL("file:/path/my.jar"));
            return super.scan(persistenceUnit, scanOptions);
        } catch (MalformedURLException e) {
            throw new IllegalStateException(e);
        }
    }
}

Answer 3

您正在设置 Hibernate 引导程序。以下是文档：https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html#bootstrap

这里基本上有两条路线可以走。您正在以特定于 Hibernate 的方式执行此操作。我通常更喜欢 JPA，因为它是最自动和最简单的一个：您将一个 persistence.xml 文件放入一个 jar 中，该 jar 将使用适当的实体注释扫描类。然后 JPA 将注入实体管理器（和工厂），然后您可以使用以下方法将其转换为本机 Hibernate 会话：

Session s = (Session) em.getDelegate();

反过来，如果需要，您应该可以访问非 JPA 功能。

如何从外部JAR

3 个答案: