hibernate annotation 双向 one-to-one 注解

环境：

Hibernate 3.3.1 Maven 3.0.4 MySQL 5.5.13 Myeclipse 8.6.1 

 

 建表语句：

DROP TABLE IF EXISTS `t_card`;CREATE TABLE `t_card` (  `cardId` int(10) unsigned NOT NULL AUTO_INCREMENT,  `cardNumber` char(18) NOT NULL,  PRIMARY KEY (`cardId`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=gb2312;INSERT INTO `t_card` VALUES ('1', '440911199008011122');

DROP TABLE IF EXISTS `t_person`;CREATE TABLE `t_person` (  `personId` int(10) unsigned NOT NULL AUTO_INCREMENT,  `personName` varchar(15) NOT NULL,  `cid` int(10) unsigned NOT NULL,  PRIMARY KEY (`personId`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=gb2312;INSERT INTO `t_person` VALUES ('1', 'fancy', '1');

 

Person.java

package com.fancy.po;import javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.OneToOne;import javax.persistence.Table;/** * ----------------------------------------- * @文件: Person.java * @作者: fancy * @邮箱: [e-mail] * @时间: 2012-6-10 * @描述: 实体类 * ----------------------------------------- *//** * @Entity 声明一个类为实体Bean * @Table(name = "xx")指定实体类映射的表,如果表名和实体类名一致,可以不指定 */@Entity@Table(name = "t_person")public class Person {    private Integer personId;    private String  personName;    private Card    card;    /**     * @Id 映射主键属性,这里采用uuid的主键生成策略      * @GeneratedValue —— 注解声明了主键的生成策略。该注解有如下属性      * strategy 指定生成的策略,默认是GenerationType. AUTO     * GenerationType.AUTO 主键由程序控制      * GenerationType.TABLE 使用一个特定的数据库表格来保存主键      * GenerationType.IDENTITY 主键由数据库自动生成,主要是自动增长类型      * GenerationType.SEQUENCE 根据底层数据库的序列来生成主键，条件是数据库支持序列      * generator 指定生成主键使用的生成器      */    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    public Integer getPersonId() {        return personId;    }    /**     * @OneToOne：一对一关联      * cascade：级联,它可以有有五个值可选,分别是：      * CascadeType.PERSIST：级联新建      * CascadeType.REMOVE : 级联删除      * CascadeType.REFRESH：级联刷新      * CascadeType.MERGE  ： 级联更新      * CascadeType.ALL    ： 以上全部四项      * @JoinColumn:主表外键字段      * cid：Person所映射的表中的一个字段      */    @OneToOne(cascade = CascadeType.ALL)    @JoinColumn(name = "cid")    public Card getCard() {        return card;    }    public String getPersonName() {        return personName;    }    public void setPersonId(Integer personId) {        this.personId = personId;    }    public void setPersonName(String personName) {        this.personName = personName;    }    public void setCard(Card card) {        this.card = card;    }}

 

Card.java

package com.fancy.po;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.OneToOne;import javax.persistence.Table;/** * ----------------------------------------- * @文件: Card.java * @作者: fancy * @邮箱: [e-mail] * @时间: 2012-6-10 * @描述: 实体类 * ----------------------------------------- */@Entity@Table(name = "t_card")public class Card {    private Integer cardId;    private String  cardNumber;    private Person  person;        @Id    @GeneratedValue(strategy = GenerationType.AUTO)    public Integer getCardId() {        return cardId;    }    /**     * @OneToOne：一对一关联      * mappedBy = "card"：意思是说这里的一对一配置参考了card     * card又是什么呢?card是Person类中的getCard(),注意不是Person类中的      * card属性,Person类中的OneToOne配置就是在getCard()方法上面配的.     * 如果Person类中的getCard()方法改成getIdCard(),其他不变的话,     * 这里就要写成：mappedBy = "idCard"     */    @OneToOne(mappedBy = "card")    public Person getPerson() {        return person;    }    public String getCardNumber() {        return cardNumber;    }    public void setCardId(Integer cardId) {        this.cardId = cardId;    }    public void setCardNumber(String cardNumber) {        this.cardNumber = cardNumber;    }    public void setPerson(Person person) {        this.person = person;    }}

 

 pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>  <groupId>com.fancy</groupId>  <artifactId>hibernate-annotation-on-to-one-example</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>hibernate-annotation-on-to-one-example</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </properties>    <dependencies>    <!-- hibernate jar -->    <dependency>      <groupId>org.hibernate</groupId>      <artifactId>hibernate-entitymanager</artifactId>      <version>3.3.1.ga</version>    </dependency>    <!-- hibernate annotation jar -->    <dependency>      <groupId>org.hibernate</groupId>      <artifactId>hibernate-annotations</artifactId>      <version>3.3.1.GA</version>    </dependency>    <!-- mysql -->    <dependency>      <groupId>mysql</groupId>      <artifactId>mysql-connector-java</artifactId>      <version>5.1.17</version>    </dependency>    <dependency>      <groupId>junit</groupId>      <artifactId>junit</artifactId>      <version>3.8.1</version>      <scope>test</scope>    </dependency>  </dependencies>  </project>

 

Test.java

package com.fancy.test;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.cfg.Configuration;import com.fancy.po.Card;import com.fancy.po.Person;/** * ----------------------------------------- * @文件: Test.java * @作者: fancy * @邮箱: [e-mail] * @时间: 2012-6-10 * @描述: 测试类 * ----------------------------------------- */public class Test {    public static void main(String[] args) {                //读取hibernate配置,默认读取classpath下的hibernate.cfg.xml        Configuration conf = new AnnotationConfiguration();            //构建session工厂         SessionFactory sessionFactory = conf.configure().buildSessionFactory();        //打开session        Session session = sessionFactory.openSession();        //开始事务         session.beginTransaction();        // * * * * * * * * * * * * * * * * * * * * * * * * * * * *        //test1(session);    //测试 1        //test2(session);    //测试 2        test3(session);      //测试 3        // * * * * * * * * * * * * * * * * * * * * * * * * * * * *        //提交事务         session.getTransaction().commit();        //关闭session工厂         sessionFactory.close();       //关闭session       session.close();    }    /**     * 数据库初始值：      * personName：fancy     * cardNumber：440911199008011122     */    //测试方法1    public static void test1(Session session){        Person person = (Person)session.get(Person.class, 1); //发出Person和Card的select语句         Card card = person.getCard();        System.out.println(person.getPersonName());        System.out.println(card.getCardNumber());        person.setPersonName("fancy");            //与初始值一致         card.setCardNumber("440911199008011122");//与初始值一致         session.save(person);    //不发出sql语句       //session.save(card);     //不发出sql语句    }    //测试方法2    public static void test2(Session session){        Person person = (Person)session.get(Person.class, 1); //发出Person和Card的select语句         Card card = person.getCard();        System.out.println(person.getPersonName());        System.out.println(card.getCardNumber());        person.setPersonName("fancyzero");        //与初始值不一致         card.setCardNumber("440911199008011122");//与初始值一致         session.save(person);    //发出Person的update语句,数据库中personName被修改,不发出Card的update语句       //session.save(card);     //发出Person的update语句,数据库中personName被修改,不发出Card的update语句    }    //测试方法3    public static void test3(Session session){        Person person = (Person)session.get(Person.class, 1); //发出Person和Card的select语句         Card card = person.getCard();        System.out.println(person.getPersonName());        System.out.println(card.getCardNumber());        person.setPersonName("fancy");           //与初始值不一致         card.setCardNumber("440911199008080808");//与初始值不一致         session.save(person);    //同时发出Person和Card的update语句,数据库中的数据相应被修改       //session.save(card);     //同时发出Person和Card的update语句,数据库中的数据相应被修改    }}