我已经为此厌倦了很长时间。我不知道是什么原因导致此错误。这是我的文件：

Uzytkownik.hbm.xml

    <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                                   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
 <class name="Uzytkownik" table="uzytkownicy">
  <id column="id" name="id" type="int"/>
  <property column="login" generated="never" lazy="false" name="login" type="string"/>
  <property column="haslo" generated="never" lazy="false" name="haslo" type="string"/>
 </class>
</hibernate-mapping>

hibernate.cfg.xml：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
                                         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory name="">
  <property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
  <property name="hibernate.connection.password">root</property>
  <property name="hibernate.connection.url">jdbc:mysql://localhost/sprawozdania</property>
  <property name="hibernate.connection.username">root</property>
  <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
  <mapping resource="com/vaannila/uzytkownik/Uzytkownik.hbm.xml"/>
 </session-factory>
</hibernate-configuration>

我使用的是MySQL 5.5。

我收到以下错误：

 Exception in thread "main" java.lang.ExceptionInInitializerError
    at com.vaannila.util.HibernateUtil.<clinit>(HibernateUtil.java:14)
    at com.vaannila.uzytkownik.Main.saveUzyt(Main.java:22)
    at com.vaannila.uzytkownik.Main.main(Main.java:16)
Caused by: org.hibernate.MappingException: entity class not found: Uzytkownik

这是我的课程：main.java

package com.vaannila.uzytkownik;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;

import javax.persistence.Entity;
import com.vaannila.util.HibernateUtil;
public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Main obj = new Main();
        String uzytkownikLogin = obj.saveUzyt("Adam", "Malysz");

    }


    public String saveUzyt(String login, String haslo){
        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = null;
        String uzytLog = null;
        try {
            transaction = session.beginTransaction();
            Uzytkownik uzyt = new Uzytkownik();
            uzyt.setLogin(login);
            uzyt.setHaslo(haslo);
            uzytLog = (String) session.save(uzyt);
            transaction.commit();
        } catch (HibernateException e) {
            transaction.rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }
        return uzytLog;
    }



}

Uzytkownik.java：

package com.vaannila.uzytkownik;
// default package
// Generated 2011-07-14 13:39:18 by Hibernate Tools 3.4.0.CR1

/**
 * Uzytkownik generated by hbm2java
 */
public class Uzytkownik implements java.io.Serializable {

    private int id;
    private String login;
    private String haslo;

    public Uzytkownik() {
    }

    public Uzytkownik(int id) {
        this.id = id;
    }

    public Uzytkownik(int id, String login, String haslo) {
        this.id = id;
        this.login = login;
        this.haslo = haslo;
    }

    public int getId() {
        return this.id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getLogin() {
        return this.login;
    }

    public void setLogin(String login) {
        this.login = login;
    }

    public String getHaslo() {
        return this.haslo;
    }

    public void setHaslo(String haslo) {
        this.haslo = haslo;
    }

}

HibernateUtil.java：

package com.vaannila.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;


    public class HibernateUtil {
        private static final SessionFactory sessionFactory;
        static {
            try {
                sessionFactory = new Configuration().configure().buildSessionFactory();
            } catch (Throwable ex) {
                System.err.println("Initial SessionFactory creation failed." + ex);
                throw new ExceptionInInitializerError(ex);

            }

        }
        public static SessionFactory getSessionFactory() {
            return sessionFactory;
        }

}