Java 如何从外部JAR加载Hibernate实体

我正在尝试从几个jar文件加载实体。 我设法做到的是

配置休眠

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);
}

因此，应该从moduleFiles数组加载实体。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.
}

外部jar（META-INF目录）中的persistence.xml

引发了一个异常：

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)

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

问题是为什么hibernate没有从jar加载带注释的实体？异常不仅由命名查询引发，而且由实体的任何其他操作引发。使用此实体之前没有错误。本地实体已正确加载

编辑：

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 ....

但当我尝试使用实体时，仍然会出现异常：

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)

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

更改是：将配置传递给jar中的每个“模块”，并添加带注释的类（所谓模块，我指的是启动时调用方法的SPI服务）

根据Hibernate only read*.hbm.xml at Configuration.addJar方法

我猜Hibernate不会自动扫描JAR，因为JPA规范中有限制

我已经在hibernate中完成了JAR的自动扫描，扩展了扫描仪并在其上添加了JAR。但您应该使用JPAAPI来实现这一点。比如：

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();

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);
        }
    }
}

---

经过3天的试验，我找到了解决方案：Hibernate使用ContextClassLoader的反射机制加载类

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

您正在设置Hibernate引导过程。以下是文件：

这里基本上有两条路线。您正在以特定于Hibernate的方式进行操作。我通常更喜欢JPA，因为它是最自动、最简单的一个：将persistence.xml文件放入jar中，jar将被扫描以查找具有适当实体注释的类。JPA随后将注入实体管理器（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，如果需要的话，应该允许您访问非JPA功能。

不幸的是，它不起作用：无法构建实体管理器工厂org.hibernate.boot.registry.classloading.spi.ClassLoadingException:无法加载类[com.antara.modules.programinfo.db.model.PrograminfoDataEntity]您是作为java se应用程序还是在jee容器中？（Wildfly中还有一个conf来代替scanner）标准JavaSE应用程序。我认为您的解决方案的问题在于ProgramInfoPersistenceUnit位于JAR中，因此在创建EntityManagerFactory时无法访问它。方法configure（File[]moduleFiles）是加载包含实体的JAR的“父级”，该实体可能与

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