public?class?HibernateUtil?{ private?static?SessionFactory?sessionFactory; private?static?Session?session; static?{ //創(chuàng)建configuration對(duì)象，讀取hibernate.cfg.xml文件，完成初始化 Configuration?config?=?new?Configuration().configure(); ServiceRegistry?serviceRegistry?=?new?ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); sessionFactory?=?config.buildSessionFactory(serviceRegistry);????????????//16 } //獲取sessionFactory public?static?SessionFactory?getSessionFactory()?{ return?sessionFactory; } //獲取session對(duì)象 public?static?Session?getSession()?{ session?=?sessionFactory.openSession(); return?session; } //關(guān)閉會(huì)話 public?static?void?closeSession(Session?session)?{ if(session!=null)?{ session.close(); } } } public?class?Test?{ public?static?void?main(String[]?args)?{ add();????????????????????????????????????????????????????????????????//14 } //將學(xué)生添加到班級(jí) public?static?void?add()? { Grade?g?=?new?Grade("java一班",?"java軟件開發(fā)一班"); Student?s1?=?new?Student("張三",?"男"); Student?s2?=?new?Student("慕女神","女"); g.getStudents().add(s1); g.getStudents().add(s2); //保存班級(jí)、學(xué)生信息 Session?session?=?HibernateUtil.getSession();????????????????????//29 Transaction?transaction?=?session.beginTransaction(); session.save(g); session.save(s1); session.save(s2); transaction.commit(); HibernateUtil.closeSession(session); } } 錯(cuò)誤信息： Exception?in?thread?"main"?java.lang.ExceptionInInitializerError at?com.imooc.entity.Test.add(Test.java:29) at?com.imooc.entity.Test.main(Test.java:14) Caused?by:?org.hibernate.MappingException:?Could?not?get?constructor?for?org.hibernate.persister.entity.SingleTableEntityPersister at?org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:185) at?org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:135) at?org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:385) at?org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1790) at?com.imooc.util.HibernateUtil.<clinit>(HibernateUtil.java:16) ...?2?more Caused?by:?org.hibernate.HibernateException:?Unable?to?instantiate?default?tuplizer?[org.hibernate.tuple.entity.PojoEntityTuplizer] at?org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:138) at?org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:188) at?org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:341) at?org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:507) at?org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:146) at?sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native?Method) at?sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown?Source) at?sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown?Source) at?java.lang.reflect.Constructor.newInstance(Unknown?Source) at?org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:163) ...?6?more Caused?by:?java.lang.reflect.InvocationTargetException at?sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native?Method) at?sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown?Source) at?sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown?Source) at?java.lang.reflect.Constructor.newInstance(Unknown?Source) at?org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:135) ...?15?more Caused?by:?org.hibernate.PropertyNotFoundException:?Could?not?find?a?getter?for?student?in?class?com.imooc.entity.Grade at?org.hibernate.property.BasicPropertyAccessor.createGetter(BasicPropertyAccessor.java:316) at?org.hibernate.property.BasicPropertyAccessor.getGetter(BasicPropertyAccessor.java:310) at?org.hibernate.mapping.Property.getGetter(Property.java:321) at?org.hibernate.tuple.entity.PojoEntityTuplizer.buildPropertyGetter(PojoEntityTuplizer.java:444) at?org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:200) at?org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:82) ...?20?more看不出哪出問題了，求解?。。?！