Hibernate无法加载具有复合id的请求类

Question

我在eclipse插件中使用Hibernate代码生成工具为world数据库生成pojo类、hbm文件和DAO类。这就产生了城市。爪哇，国家。java，Countrylanguage。java和CountrylanguageId。java，但只有三个hbm文件。hbm。xml国家/地区。hbm。xml和Countrylanguage。hbm。xml。

我已经通过addClass在配置中添加了java类文件

    protected SessionFactory getSessionFactory() {
    Configuration config = new Configuration()
            .configure("hibernate.cfg.xml")
            .addClass(Country.class)
            .addClass(City.class)
            .addClass(Countrylanguage.class);

但是在尝试使用创建服务注册表时

StandardServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(config.getProperties()).build();

它会引发以下错误-

Exception in thread "main" org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.component.PojoComponentTuplizer]
at org.hibernate.tuple.component.ComponentTuplizerFactory.constructTuplizer(ComponentTuplizerFactory.java:107)
at org.hibernate.tuple.component.ComponentTuplizerFactory.constructDefaultTuplizer(ComponentTuplizerFactory.java:128)
at org.hibernate.tuple.component.ComponentMetamodel.<init>(ComponentMetamodel.java:77)
at org.hibernate.tuple.component.ComponentMetamodel.<init>(ComponentMetamodel.java:52)
at org.hibernate.mapping.Component.getType(Component.java:227)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:455)
at org.hibernate.mapping.RootClass.validate(RootClass.java:268)
at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:343)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:461)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at dao.DefaultService.getSessionFactory(DefaultService.java:24)
at dao.DefaultService.<init>(DefaultService.java:14)
at dao.CityService.<init>(CityService.java:21)
at App.main(App.java:6)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.hibernate.tuple.component.ComponentTuplizerFactory.constructTuplizer(ComponentTuplizerFactory.java:104)
... 13 more
Caused by: org.hibernate.MappingException: component class not found: CountrylanguageId
at org.hibernate.mapping.Component.getComponentClass(Component.java:177)
at org.hibernate.tuple.component.PojoComponentTuplizer.setComponentClass(PojoComponentTuplizer.java:147)
at org.hibernate.tuple.component.AbstractComponentTuplizer.<init>(AbstractComponentTuplizer.java:37)
at org.hibernate.tuple.component.PojoComponentTuplizer.<init>(PojoComponentTuplizer.java:41)
... 18 more
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [CountrylanguageId]
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:133)
at org.hibernate.mapping.Component.getComponentClass(Component.java:174)
... 21 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : CountrylanguageId
at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:130)
... 22 more

我试着添加

.addClass（CountrylanguageId.class）

但这引发了另一个错误，即相应的hbm文件Countrylanguage。hbm。缺少xml。

基于复合id关系生成的类是否需要hbm文件？为什么即使在hibernate配置实例中指定了类，也会出现这种错误？

Answer 1

解决了问题。在生成pojo类时，我使用hibernate工具将其指定为默认包，但在子文件夹src/main/java/entity下生成它们。

hbm文件已更新为类=“…”引用和名称=“…”引用为实体。Countrylanguage，之后它运行良好。

还验证了使用hibernate生成工具，将包配置为实体，将文件夹配置为默认src/main/java，可以按预期正确输出hbm文件。

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