org.hibernate.MappingException:未知实体

问题描述

我正在尝试完成 Beginning Hibernate 2nd edition，但我一直在尝试将简单的工作示例与 HSQLDB 放在一起.

I'm trying to work through Beginning Hibernate 2nd edition, and I'm stuck trying to put together the simple working example with HSQLDB.

当我运行 ant populateMessages 时，我得到

When I run ant populateMessages, I get

[java] org.hibernate.MappingException: Unknown entity: sample.entity.Message
[java]     at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:194)
[java]     at org.apache.tools.ant.taskdefs.Java.run(Java.java:747)
...

这是我所拥有的:

Message.java

package sample.entity;

import org.hibernate.annotations.Entity;

import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
public class Message
{
    private String messageText;
    private Integer id;

    public Message( String messageText )
    {
        this.messageText = messageText;
    }

    public Message()
    {
    }

    public String getMessageText()
    {
        return messageText;
    }

    public void setMessageText(String messageText)
    {
        this.messageText = messageText;
    }

    @Id
    @GeneratedValue
    public Integer getId()
    {
        return id;
    }

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

PopulateMessages.java

package sample;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;
import sample.entity.Message;

import java.util.Date;

public class PopulateMessages
{
    public static void main(String[] args)
    {
        SessionFactory factory = new AnnotationConfiguration().configure().buildSessionFactory();
        Session session = factory.openSession();
        session.beginTransaction();

        Message m1 = new Message("Hibernated a  messages on " + new Date());
        session.save(m1);
        session.getTransaction().commit();
        session.close();
    }
}

build.properties

# Path to the hibernate install directory
hibernate.home=C:/hibernate/hibernate-3.5.6
# Path to the hibernate-tools install directory
hibernate.tools.home=C:/hibernate/hibernate-tools
# Path to hibernate-tools.jar relative to hibernate.tools.home
hibernate.tools.path=/plugins/org.hibernate.eclipse_3.3.1.v201006011046R-H111-GA/lib/tools
# Path to hibernate-tools hibernate libraries relative to hibernate.tools.home
hibernate.tools.lib.path=/plugins/org.hibernate.eclipse_3.3.1.v201006011046R-H111-GA/lib/hibernate
# Path to the SLF4J implementation JAR for the logging framework to use
slf4j.implementation.jar=lib/slf4j-simple-1.6.1.jar
# Path to the HSQL DB install directory
hsql.home=C:/hsqldb

hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
 "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.url">
jdbc:hsqldb:file:testdb;shutdown=true
</property>
<property name="hibernate.connection.driver_class">
org.hsqldb.jdbcDriver
</property>
<property name="hibernate.connection.username">sa</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.connection.pool_size">0</property>
<property name="hibernate.dialect">
org.hibernate.dialect.HSQLDialect
</property>
<property name="hibernate.show_sql">false</property>
<!-- "Import" the mapping resources here -->
<mapping class="sample.entity.Message"/>
</session-factory>
</hibernate-configuration>

build.xml

<project name="sample">
    <property file="build.properties"/>
    <property name="src" location="src"/>
    <property name="bin" location="bin"/>
    <property name="sql" location="sql"/>
    <property name="hibernate.tools"
              value="${hibernate.tools.home}${hibernate.tools.path}"/>
    <path id="classpath.base">
        <pathelement location="${src}"/>
        <pathelement location="${bin}"/>
        <pathelement location="${hibernate.home}/hibernate3.jar"/>
        <pathelement location="${slf4j.implementation.jar}"/>
        <fileset dir="${hibernate.home}/lib" includes="**/*.jar"/>
        <pathelement location="${hsql.home}/lib/hsqldb.jar"/>
  <fileset dir="./lib" includes="**/*.jar"/>
    </path>
<path id="classpath.tools">
    <path refid="classpath.base"/>
    <pathelement
            location="${hibernate.tools.home}/${hibernate.tools.lib.path}/commons-logging-1.0.4.jar"/>
    <pathelement
            location="${hibernate.tools}/freemarker.jar"/>
    <pathelement
            location="${hibernate.tools}/hibernate-tools.jar"/>
</path>
<taskdef name="htools"
         classname="org.hibernate.tool.ant.HibernateToolTask"
         classpathref="classpath.tools"/>
<target name="exportDDL" depends="compile">
    <mkdir dir="${sql}"/>
    <htools destdir="${sql}">
        <classpath refid="classpath.tools"/>
        <annotationconfiguration
                configurationfile="${src}/hibernate.cfg.xml"/>
        <hbm2ddl drop="true" outputfilename="sample.sql"/>
    </htools>
</target>
<target name="compile">
    <javac srcdir="${src}" destdir="${bin}" classpathref="classpath.base"/>
</target>
<target name="populateMessages" depends="compile">
    <java classname="sample.PopulateMessages" classpathref="classpath.base"/>
</target>
<target name="listMessages" depends="compile">
    <java classname="sample.ListMessages" classpathref="classpath.base"/>
</target>

推荐答案

您的实体未正确注释，您必须使用 @javax.persistence.Entity 注释.您可以使用 Hibernate 扩展 @org.hibernate.annotations.Entity 超出了 JPA 所提供的范围，但 Hibernate 注释不是替代品，而是补充.

You entity is not correctly annotated, you must use the @javax.persistence.Entity annotation. You can use the Hibernate extension @org.hibernate.annotations.Entity to go beyond what JPA has to offer but the Hibernate annotation is not a replacement, it's a complement.

因此将您的代码更改为:

So change your code into:

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
public class Message {
    ...
}

参考资料

• Hibernate 注释参考指南
  • 2.4.Hibernate 注释扩展

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