Question

我正在尝试学习使用MySQL的Hibernate，我从来没有使用过它之前和之后的一系列错误我最终都被这个问题所困扰：

Exception in thread "main" org.hibernate.hql.internal.ast.QuerySyntaxException: country is not mapped [from country]
    at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:180)
    at org.hibernate.hql.internal.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:110)
    at org.hibernate.hql.internal.ast.tree.FromClause.addFromElement(FromClause.java:93)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:324)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3291)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3180)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:706)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:562)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:299)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:247)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:248)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:105)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:168)
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:221)
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:199)
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1735)
    at org.hibernate.tutorial.hbm.Test.main(Test.java:37)

我尝试过另一个问题的可能解决方案，但没有，它不起作用。这是我到目前为止所做的：

hibernate.cfg.xml （Folder src）

<?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> 
        <!-- Database connection settings --> 
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 
        <property name="connection.url">jdbc:mysql://localhost:3306/stock</property> 
        <property name="connection.username">root</property> 
        <property name="connection.password">root</property>   

        <!-- JDBC connection pool (use the built-in) --> 
        <property name="connection.pool_size">1</property>   

        <!-- SQL dialect --> 
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>   

        <!-- Echo all executed SQL to stdout --> 
        <property name="show_sql">true</property>   
        <property name="format_sql">true</property>
        <property name="hbm2ddl.auto">create</property>

        <!-- configuration pool via c3p0-->
        <property name="c3p0.acquire_increment">1</property>
        <property name="c3p0.idle_test_period">3600</property> <!-- seconds -->
        <property name="c3p0.min_size">3</property>
        <property name="c3p0.max_size">5</property>
        <property name="c3p0.max_statements">0</property>
        <property name="c3p0.timeout">3605</property> <!-- seconds -->
        <property name="hibernate.c3p0.preferredTestQuery">select 1;</property>

        <!-- Mapping files --> 
        <!--<mapping resource="country.hbm.xml"/> -->
    </session-factory> 
</hibernate-configuration>

country.hbm.xml （文件夹* src \ main \ resources \ org \ hibernate \ tutorial \ hbm * ）

<?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="org.hibernate.tutorial.hbm.country" table="country">
        <id name="id_country">
        <property name="country"/>
    </class>
</hibernate-mapping>

country.java

package org.hibernate.tutorial.hbm;

public class country {
    private int id_country;
    private String country;

    public int getId_country() {
        return id_country;
    }
    public void setId_country(int id_country) {
        this.id_country = id_country;
    }
    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }

}

Test.java

package org.hibernate.tutorial.hbm;

import java.util.List;

import org.hibernate.SessionFactory;
import org.hibernate.Session;
//import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tutorial.hbm.country; /* required for test function only */

public class Test {

    private static final SessionFactory sessionFactory;

        static {
            try {
                // Initialize factory using contents of hibernate.cfg.xml
                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;
    }

    public static void main (String[] args) {

        country mycls = new country();
        /* the id field will auto-increment to a unique value which will distinguish records */
        //mycls.setCountry("My Property");
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        List result = session.createQuery( "from country" ).list();
        for ( country ctry : (List<country>) result ) {
            System.out.println( "Country (" + ctry.getId_country() + ") : " + ctry.getCountry() );
        }
        session.getTransaction().commit();
        session.close(); /* if this test succeeds, you'll find a new record in your MySQL database */

    }

}

- 编辑20130301

我已经改变了你的建议几件事

hibernate.cfg.xml中

<!-- Mapping files --> 
<mapping resource="org/hibernate/tutorial/hbm/Country.hbm.xml"/>

我重命名并移动了文件Country.hbm.xml（它是country.hbm.xml）并更改了此

<class name="Country" table="country">
<!-- <class name="org.hibernate.tutorial.hbm.country" table="country"> -->

文件已移至 src \ org \ hibernate \ tutorial \ hbm

类country.java已重命名为Country.java

最后在Test.java中修改了这一行

List result = session.createQuery( "from Country" ).list();
        for ( Country ctry : (List<Country>) result ) {
            System.out.println( "Country (" + ctry.getId_country() + ") : " + ctry.getCountry() );
        }

现在我将此视为错误

Initial SessionFactory creation failed.org.hibernate.InvalidMappingException: Could not parse mapping document from resource org/hibernate/tutorial/hbm/Country.hbm.xml
Exception in thread "main" java.lang.ExceptionInInitializerError
    at org.hibernate.tutorial.hbm.Test.<clinit>(Test.java:21)
Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from resource org/hibernate/tutorial/hbm/Country.hbm.xml
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXml(Configuration.java:3423)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXmlQueue(Configuration.java:3412)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3400)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1330)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1730)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1781)
    at org.hibernate.tutorial.hbm.Test.<clinit>(Test.java:18)
Caused by: org.hibernate.MappingException: class Country not found while looking for property: id_country
    at org.hibernate.internal.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:232)
    at org.hibernate.mapping.SimpleValue.setTypeUsingReflection(SimpleValue.java:324)
    at org.hibernate.cfg.HbmBinder.bindSimpleId(HbmBinder.java:449)
    at org.hibernate.cfg.HbmBinder.bindRootPersistentClassCommonValues(HbmBinder.java:382)
    at org.hibernate.cfg.HbmBinder.bindRootClass(HbmBinder.java:322)
    at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:173)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXml(Configuration.java:3420)
    ... 6 more
Caused by: java.lang.ClassNotFoundException: Country
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at org.hibernate.internal.util.ReflectHelper.classForName(ReflectHelper.java:192)
    at org.hibernate.internal.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:228)
    ... 12 more

感谢您的帮助。谢谢。

Answer 1

您的country.hbm.xml格式错误：

<id name="id_country">

是一个永不关闭的开放标记。我怀疑你的意思是：

<id name="id_country"/>

（注意结束斜线）。

然后（正如@RameshK指出的那样），你必须添加

<mapping resource="org/hibernate/tutorial/hbm/country.hbm.xml"/>

到您的hibernate.cfg.xml文件。

一个小问题：根据正常的编码约定，Java中的类是大写的，因此我将country更改为Country。

Answer 2

我终于解决了这个问题，在我在那里编辑了答案中的所有内容之后，我将Country.hbm.xml文件修改为:(注意注释行）

<?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="Country" table="country"> -->
    <class name="org.hibernate.tutorial.hbm.Country" table="country">
        <id name="id_country"/>
        <property name="country"/>
    </class>
</hibernate-mapping>

必须是org.hibernate.tutorial.hbm.Country而不是org.hibernate.tutorial.hbm.country

org.hibernate.hql.internal.ast.QuerySyntaxException：表未映射[来自表]

- 编辑20130301

2 个答案: