主键共享方式和外键方式一对一双向关系映射(参考张龙老师的例子)

1.学生类：Student.java

package org.yang.hibernate.model;

public class Student

{

    private String id;

    private String name;

    private IdCard idCard;

    

    public Student(){}

    public String getId() {

        return id;

    }

    public String getName() {

        return name;

    }

    public IdCard getIdCard() {

        return idCard;

    }

    public void setId(String id) {

        this.id = id;

    }

    public void setName(String name) {

        this.name = name;

    }

    public void setIdCard(IdCard idCard) {

        this.idCard = idCard;

    }

}

2.身份证类：IdCard.java

package org.yang.hibernate.model;

public class IdCard

{

    private String id;

    private int number;

    private Student student;

    

    public IdCard(){}

    public String getId() {

        return id;

    }

    public int getNumber() {

        return number;

    }

    public Student getStudent() {

        return student;

    }

    public void setId(String id) {

        this.id = id;

    }

    public void setNumber(int number) {

        this.number = number;

    }

    public void setStudent(Student student) {

        this.student = student;

    }

}

3.学生类的映射文件：Student.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="org.yang.hibernate.model.Student" table="student">

        <id name="id" column="id" type="string">

            <generator class="uuid"></generator>

        </id>

        <property name="name" column="name" type="string"></property>

        

        <one-to-one name="idCard" class="org.yang.hibernate.model.IdCard" cascade="all" fetch="join">

        </one-to-one>

        

    </class>

</hibernate-mapping>

4.身份证类的映射文件：IdCard.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="org.yang.hibernate.model.IdCard" table="idcard">

        <id name="id" column="id">

            <generator class="foreign">

                <!--

                     根据当前类IdCard的哪一个属性的名字来生成.

                     在Student的hbm根据IdCard来生成也是可以的。

                     这根据个人喜好

                 -->

                <param name="property">student</param>

            </generator>

        </id>

        

        <property name="number" column="number" type="integer"></property>

        

        <one-to-one name="student" class="org.yang.hibernate.model.Student"></one-to-one>

        <!--

        外键关联，本质上就是一对多的蜕化形式。在many-to-one元素中增加unique="true"就成了一对一

        当修改成这个样子时，也不要忘记了将<id>元素的主键生成方式也改掉。改为：

　　<id name="id" column="id">

            <generator class="uuid" />

      </id>

        <many-to-one name="student" unique="true" class="org.yang.hibernate.model.Student" column="student_id"/>

        -->

    </class>

</hibernate-mapping>

5.总配置文件：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>

        <property name="connection.driver_class">org.postgresql.Driver</property>

        <property name="connection.url">jdbc:postgresql://localhost:5432/hibernate</property>

        <property name="hibernate.connection.username">postgres</property>

        <property name="hibernate.connection.password">yang</property>

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

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

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

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

        

        <mapping resource="IdCard.hbm.xml"/>

        <mapping resource="Student.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

6.生成数据库表的代码文件：CreateTable.java

package org.yang.hibernate;

import org.hibernate.cfg.Configuration;

import org.hibernate.tool.hbm2ddl.SchemaExport;

public class CreateTable

{

    public static void main(String[] args)

    {

        SchemaExport export = new SchemaExport(new Configuration().configure());

        export.create(true, true);

    }

}

7.测试文件：HibernateTest.java

package org.yang.hibernate;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.yang.hibernate.model.IdCard;

import org.yang.hibernate.model.Student;

public class HibernateTest

{

    private static final SessionFactory sessionFactory;

    static {

        try

        {

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

        }

        catch(Throwable ex)

        {

            System.err.println("Initial SessionFactory failed " + ex);

            throw new ExceptionInInitializerError(ex);

        }

    }

    

    public static void main(String[] args)

    {

     

        Student student = new Student();

        student.setName("yangzhiyong");

        

        IdCard idCard = new IdCard();

        idCard.setNumber(987654);

        

        student.setIdCard(idCard);

        idCard.setStudent(student);

        

        Session session = sessionFactory.openSession();

        Transaction tx = null;

        try

        {

            tx = session.beginTransaction();

            session.save(student);

            tx.commit();

        }

        catch (Exception e)

        {

            if (null != tx)

            {

                tx.rollback();

            }

            e.printStackTrace();

        }

        finally

        {

            session.close();

        }

  }

}