org.hibernate.MappingException：未知实体：Library.Model.Person

Question

@Entity
@Table(name = "PERSON")
public class Person implements Serializable {

// Attributes.    
@Id
@Column(name = "ID", unique = true, nullable = false)    
@GeneratedValue(strategy=GenerationType.AUTO)
private Integer id;

@Column(name = "NAME", nullable = false, length=50)      
private String name;

@Column(name = "ADDRESS", nullable = false, length=100)
private String address;

@Column(name = "TELEPHONE", nullable = false, length=10)
private String telephone;

@Column(name = "EMAIL", nullable = false, length=50)
private String email;

@OneToMany(cascade=CascadeType.ALL, fetch = FetchType.LAZY)
@JoinColumn(name="PERSON_ID")   
private List<Book> books;

// Constructors.
public Person() {
    this.id = 0;
    this.name = ("");
    this.address = ("");
    this.telephone = ("");
    this.email = ("");
    this.books = null;
}

此实体由Spring控制器管理，方法如下：

@RequestMapping(value = "/register", method = RequestMethod.POST)
public String post(@ModelAttribute("person") Person person, 
                   BindingResult bindingResult, 
                   SessionStatus sessionStatus,
                   Model model /* , 
                   HttpSession session */) throws DAOException {                  
    logger.info(PersonController.class.getName() + ".post() method called.");

    personValidator.validate(person, bindingResult);
    if (bindingResult.hasErrors()) {
        return "register";
    }
    else {

        // Write Person to database.
        personService.insert(person);

        // Set view.
        sessionStatus.setComplete();             
        return "options";            
    }
} 

服务类别为：

@Service("personService")
@Transactional
public class PersonService {

@Autowired 
PersonDAO personDAO;

public void insert(Person person) throws DAOException {
    personDAO.insert(person);
}

而DAO是这样的：

@Repository("PersonDAO")
public class PersonDAOImpl implements PersonDAO {

@Autowired
private SessionFactory sessionFactory;
static final Logger logger = Logger.getLogger(PersonDAOImpl.class.getName()); 

@Override
public void insert(Person person) throws DAOException {
    logger.info(PersonDAOImpl.class.getName() + ".insert() method called.");

    Session session = sessionFactory.openSession();
    Transaction transaction = session.getTransaction();
    try {
        transaction.begin();
        session.save(person);
        transaction.commit();
    }
    catch(RuntimeException e) {
        transaction.rollback();
        throw new DAOException(e);
    }
    finally {
        session.close();
    }
}

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource"></property>        
    <property name="hibernateProperties">
        <props>
           <prop key="hibernate.dialect">org.hibernate.dialect.DerbyDialect</prop>
           <prop key="hibernate.show_sql">true</prop>
           <prop key="hibernate.current_session_context_class ">thread</prop>

           <!-- What to do with the database schema. -->
           <prop key="hbm2ddl.auto">validate</prop>    
           <!-- validate:    validate the schema, makes no changes to the database.
                update:      update the schema.
                create:      creates the schema, destroying previous data.
                create-drop: drop the schema at the end of the session. -->                 
        </props>            
    </property>                    
</bean>

org.hibernate.MappingException: Unknown entity: library.model.Person

<property name="packagesToScan" value="library.model" /> 

<property name="annotatedClasses">
        <list>
            <value>library.model.Person</value>
        </list>
    </property>   

Answer 1

尝试替换：

<property name="annotatedClasses">
    <list>
        <value>library.model.Person</value>
    </list>
</property>  

与：

<property name="packagesToScan">
   <list>
       <value>library.model</value>
    </list>
</property>

在您的sessionFactory属性中。

<dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-orm</artifactId>
   <version>YOUR SPRING VERSION HERE</version>
</dependency>