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Hibernate的映射关系很多，也比较复杂，也很容易忘记。这个基本上占据了Hibernate学习的七成时间。熟悉这些映射模型，需要大量的实践才能掌握。下面是我对Hibernate关联关系映射的一个总结，放到blog上一是自己查看方便，二来也可以和更多Hibernate开发人员交流分享。希望各位多多留言哦：）。

 

Hibernate关联关系映射目录

│ 

├─单向关联

│  ├─  一对一外键单向关联
│  ├─  一对一主键单向关联

│  ├─  一对一连接表单向关联
│  ├─  一对多外键单向关联

│  ├─  一对多连接表单向关联

│  ├─  多对一外键单向关联

│  ├─  多对一连接表单向关联

│  └─  多对多单向关联

└─双向关联

    ├─  一对一外键双向关联

    ├─  一对一主键双向关联
    ├─  一对一连接表双向关联

    ├─  一对多外键双向关联

    ├─  一对多连接表双向关联

    └─  多对多双向关联

 

 

本系列实例的开发环境：

 

Windows XP Professional 简体中文版

MySQL 5.0.45

Hibernate 3.12

Java SDK 1.5.06

IntelliJ IDEA 5.12

 

系列实例中所用的Hibernate配置文件如下：

 

<?xml version='1.0' encoding='gb2312'?>

<!DOCTYPE hibernate-configuration PUBLIC

        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

        "[url]http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd[/url]">

<hibernate-configuration>

    <session-factory>

        <!--指定连接数据库驱动-->

        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>

        <!--指定连接数据库的url，hibernate连接的数据库名-->

        <property name="connection.url">jdbc:mysql://localhost:3306/hbstudy</property>

        <!--指定连接数据库的用户名-->

        <property name="connection.username">root</property>

        <!--指定连接数据库的用户密码-->

        <property name="connection.password">leizhimin</property>

        <!--指定连接池的大小-->

        <property name="connection.pool_size">5</property>

        <!--指定数据库的方言-->

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

        <!--根据需要自动创建数据库,测试环境用-->

        <property name="hbm2ddl.auto">create</property>

        <!--在控制台显示执行的SQL语句-->

        <property name="show_sql">true</property>

        <!-- Enable Hibernate's automatic session context management -->

        <property name="current_session_context_class">thread</property>

        <!--映射文件列表-->

        <!--单向关联-->

        <mapping resource="com/lavasoft/dx/_n_1_fk/Addressn1fk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_n_1_fk/Personn1fk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_n_1_tab/Addressn1tab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_n_1_tab/Personn1tab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_fk/Address11fk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_fk/Person11fk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_tab/Address11tab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_tab/Person11tab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_pk/Address11pk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_1_pk/Person11pk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_n_fk/Address1nfk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_n_fk/Person1nfk.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_n_tab/Address1ntab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_1_n_tab/Person1ntab.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_n_n/Addressnn.hbm.xml"/>

        <mapping resource="com/lavasoft/dx/_n_n/Personnn.hbm.xml"/>

        <!--双向关联-->

        <mapping resource="com/lavasoft/sx/_1_n_fk/Address1nfk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_n_fk/Person1nfk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_n_tab/Address1ntab_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_n_tab/Person1ntab_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_n_n/Addressnn_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_n_n/Personnn_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_fk/Address11fk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_fk/Person11fk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_pk/Address11pk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_pk/Person11pk_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_tab/Address11tab_sx.hbm.xml"/>

        <mapping resource="com/lavasoft/sx/_1_1_tab/Person11tab_sx.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

 

系列实例中所用到Session工厂是：

public class HibernateUtil {

    private static final SessionFactory sessionFactory;

    static {

        try {

            // Create the SessionFactory from hibernate.cfg.xml

            sessionFactory = new Configuration().configure().buildSessionFactory();

        } catch (Throwable ex) {

            // Make sure you log the exception, as it might be swallowed

            System.err.println("初始化SessionFactory失败！" + ex);

            throw new ExceptionInInitializerError(ex);

        }

    }

    public static final ThreadLocal session = new ThreadLocal();

    public static Session getCurrentSession() throws HibernateException {

        Session s = (Session) session.get();

        //当原Session为空或已关闭时，打开一个新的Session

        if (s == null || !s.isOpen()) {

            s = sessionFactory.openSession();

            session.set(s);

        }

        return s;

    }

    public static void closeSession() throws HibernateException {

        Session s = (Session) session.get();

        session.set(null);

        if (s != null) {

            s.close();

        }

    }

}