QuerySyntaxException问题：未映射表[from table]

Question

我对使用Hibernate是陌生的，遇到一个错误，尝试修复时遇到很多麻烦。我搜索了其他类似Stackoverflow的帖子，但这些解决方案对我不起作用。

这是错误：

Jul 14, 2019 6:43:53 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.1.5.Final}
Jul 14, 2019 6:43:53 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
Jul 14, 2019 6:43:53 PM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
Jul 14, 2019 6:43:53 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
Jul 14, 2019 6:43:53 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Jul 14, 2019 6:43:53 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/scheduler]
Jul 14, 2019 6:43:53 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=root, password=****}
Jul 14, 2019 6:43:53 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Jul 14, 2019 6:43:53 PM org.hibernate.engine.jdbc.connections.internal.PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Jul 14, 2019 6:43:54 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
Jul 14, 2019 6:43:54 PM org.hibernate.hql.internal.QueryTranslatorFactoryInitiator initiateService
INFO: HHH000397: Using ASTQueryTranslatorFactory
Exception in thread "main" org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped [from User]
    at org.hibernate.hql.internal.ast.QuerySyntaxException.generateQueryException(QuerySyntaxException.java:79)
    at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150)
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:302)
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:240)
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1907)
    at DAO.UserDAO.getUsers(UserDAO.java:32)
    at classes.Test.main(Test.java:12)
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped
    at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:171)
    at org.hibernate.hql.internal.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:91)
    at org.hibernate.hql.internal.ast.tree.FromClause.addFromElement(FromClause.java:79)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:324)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3690)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3579)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:718)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:574)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:311)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:259)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:262)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:190)
    ... 9 more

hibernate.cfg.xml文件：（src \ main \ resources）

<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/scheduler</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">admin</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <mapping resource="mappings/User.hbm.xml" />

    </session-factory>
</hibernate-configuration>

这是User.hbm.xml文件：（src \ main \ resources \ mappings）

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="classes.User" table="users">
        <id name="id">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="name" type="string">
            <column name="name"/>
        </property>
        <property name="phoneNumber" type="string">
            <column name="phone_number"/>
        </property>

    </class>
</hibernate-mapping>

这是User.java（src \ main \ java \ classes）

package classes;

import java.io.Serializable;
import java.util.List;

public class User implements Serializable{

    private static final long serialVersionUID = 1L;
    private int id;
    private String name;
    private String phoneNumber;
    private List<Event> events;


    public User() {

    }

    /**
     * @return the id
     */
    public int getId() {
        return id;
    }
    /**
     * @param id the id to set
     */
    public void setId(int id) {
        this.id = id;
    }
    /**
     * @return the name
     */
    public String getName() {
        return name;
    }
    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }
    /**
     * @return the phoneNumber
     */
    public String getPhoneNumber() {
        return phoneNumber;
    }
    /**
     * @param phoneNumber the phoneNumber to set
     */
    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }
    /**
     * @return the events
     */
    public List<Event> getEvents() {
        return events;
    }
    /**
     * @param events the events to set
     */
    public void setEvents(List<Event> events) {
        this.events = events;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", phoneNumber=" + phoneNumber + ", events=" + events + "]";
    }

}

我的test.java

package classes;

import DAO.UserDAO;

public class Test {


       public static void main(String[] args) {
           UserDAO dao = new UserDAO();

           System.out.println(dao.getUsers());




       }

}

还有UserDAO

package DAO;


import java.util.List;
import org.hibernate.Session;
import org.hibernate.Transaction;

import Hibernate.HibernateUtil;
import classes.User;

public class UserDAO {

    public void saveUser(User user) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();
            // save the student object
            session.save(user);
            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }
    @SuppressWarnings("unchecked")
    public List <User> getUsers() {
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            return session.createQuery("from User").list();
        }
    }
}

HibernateUtil：

package Hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateUtil {
    private static SessionFactory sessionFactory;

    public static SessionFactory getSessionFactory() {
        try {
            if (sessionFactory == null) {
                // loads configuration and mappings
                Configuration configuration = new Configuration().configure();
                ServiceRegistry serviceRegistry
                    = new StandardServiceRegistryBuilder()
                        .applySettings(configuration.getProperties()).build();

                // builds a session factory from the service registry
                sessionFactory = configuration.buildSessionFactory(serviceRegistry);           
            }
        } catch (Exception e) {
            e.printStackTrace();

        }    

        return sessionFactory;
    }
}

任何帮助将不胜感激。我已经坚持了一段时间了。