Hibernate未知实体（不缺少@Entity或导入javax.persistence.Entity）
我有一个非常简单的课程：
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name = "users") public class User { @Column(name = "firstName") private String firstName; @Column(name = "lastName") private String lastName; @Column(name = "email") private String email; @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name = "id") private long id; public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public long getId() { return id; } public void setId(long id) { this.id = id; } } 我用这个主要来称它：
public class Main { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub HibernateUtil.buildSessionFactory(); Session session = HibernateUtil.getSessionFactory().getCurrentSession(); session.beginTransaction(); User u = new User(); u.setEmail("david@hello.co.uk"); u.setFirstName("David"); u.setLastName("Gray"); session.save(u); session.getTransaction().commit(); System.out.println("Record committed"); session.close(); } }
我一直得到这个MappingException：
Exception in thread "main" org.hibernate.MappingException: Unknown entity: org.assessme.com.entity.User at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:1172) at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1316) at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:204) at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:189) at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90) at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:670) at org.hibernate.internal.SessionImpl.save(SessionImpl.java:662) at org.hibernate.internal.SessionImpl.save(SessionImpl.java:658) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at org.hibernate.context.internal.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:352) at $Proxy4.save(Unknown Source) at Main.main(Main.java:20)
我的HibernateUtil是：
import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import org.hibernate.service.ServiceRegistry; import org.hibernate.service.ServiceRegistryBuilder; public class HibernateUtil { private static SessionFactory sessionFactory; private static ServiceRegistry serviceRegistry; public static SessionFactory buildSessionFactory() { try { // Create the SessionFactory from hibernate.cfg.xml Configuration configuration = new Configuration(); configuration.configure(); serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry(); return new Configuration().configure().buildSessionFactory(serviceRegistry); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { sessionFactory = new Configuration().configure().buildSessionFactory(serviceRegistry); return sessionFactory; } }
有没有人有任何想法，因为我看了很多重复，但决议似乎并不适合我。 这是我的hibernate.cfg.xml：
com.mysql.jdbc.Driver jdbc:mysql://localhost/ssme root mypassword 1 org.hibernate.dialect.MySQLDialect thread org.hibernate.cache.NoCacheProvider true update
您应该使用AnnotationConfiguration而不是Configuration ，然后调用
configuration.addAnnotatedClass(User.class);
将您的类添加到映射类的列表中。
在之前添加到hibernate.cfg.xml ：
考虑使用此处描述的AnnotationConfiguration 。
您可以使用其addClass(User.class)方法，或者如果您持久保存多个实体，则使用addPackage("org.assessme.com.entity")方法。
你有点像这个HibernateUtil类重新发明轮子。 考虑使用Spring，这样你就可以利用它的AnnotationSessionFactoryBean 。
我忘了将hbm.xml映射添加到我的cfg.xml文件中。 一旦我添加它，这个exception就消失了。
将以下行添加到您的hibernate.cfg.xml中
你有任何persistence.xml或hibernate.cfg.xml吗？ 如果你必须在其中添加你的映射类，那么hibernate会理解你的类正在映射到数据库。 如果您有hibernate.cfg.xml ，可以像这样添加