Hibernate一對一外鍵雙向關聯(xml配置篇)

轉載地址：http://www.blogjava.net/sxyx2008/archive/2010/10/18/335454.html

Husband.java

package com.one2one.bean;


public class Husband {
    
    private int id;
    private String name;
    private Wife wife;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Wife getWife() {
        return wife;
    }
    public void setWife(Wife wife) {
        this.wife = wife;
    }
    
}

Wife.java

package com.one2one.bean;

public class Wife {
    
    private int id;
    private String name;
    private Husband husband;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Husband getHusband() {
        return husband;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }
    
}

映射文件
Husband.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 package="com.one2one.bean">
        <class name="Husband" table="husband" catalog="Hibernate_One2One_fk">
            <id name="id" column="id">
                <generator class="native"/>
            </id>
            <property name="name" column="name"/>
            <one-to-one name="wife" class="Wife" property-ref="husband"/>
        </class>
    </hibernate-mapping>

<one-to-one name="wife" class="Wife" property-ref="husband"/> property-ref後的husband爲Wife中定義的husband屬性
Wife.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 package="com.one2one.bean">
        <class name="Wife" table="wife" catalog="Hibernate_One2One_fk">
            <id name="id" column="id">
                <generator class="native"/>
            </id>
            <property name="name" column="name"/>
            <many-to-one name="husband" column="husband_id" unique="true" />
        </class>
    </hibernate-mapping>

<many-to-one name="husband" column="husband_id" unique="true" />
many-to-one的作用是在wife表中生成一個外鍵husband_id,且唯一,並參照husband表中的主鍵
用hibernate的hbm2ddl導出的sql

create table Hibernate_One2One_fk.husband (
        id integer not null auto_increment,
        name varchar(255),
        primary key (id)
    )

    create table Hibernate_One2One_fk.wife (
        id integer not null auto_increment,
        name varchar(255),
        husband_id integer unique,
        primary key (id)
    )

    alter table Hibernate_One2One_fk.wife 
        add index FK37AF119039AEDD (husband_id), 
        add constraint FK37AF119039AEDD 
        foreign key (husband_id) 
        references Hibernate_One2One_fk.husband (id)

測試示例

@Test
    public void save(){
        Session session=HibernateSessionFactory.getSession();
        Transaction transaction=session.beginTransaction();
        try {
            transaction.begin();
            Husband husband=new Husband();
            husband.setName("張三");
            session.save(husband);
            Wife wife=new Wife();
            wife.setName("如花");
            wife.setHusband(husband);
            session.save(wife);
            transaction.commit();
        } catch (HibernateException e) {
            e.printStackTrace();
        }
    }
    
    @Test
    public void select(){
        Session session=HibernateSessionFactory.getSession();
        Husband husband=(Husband) session.get(Husband.class, 1);
        System.out.println(husband.getName());
        System.out.println(husband.getWife().getName());
    }