hibernate的一对一映射的例子

//IdCard.hbm.xml的代码

 

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
 package="com.totalOne2one">
  <class name="IdCard">

  <id name="id">
   <generator class="foreign"><!--采用外间生成方式生成主键值-->
<!--表示取Person的主键值生成IdCard的主键值，这里的person要与下面的one2one里面的属性值一致-->
            <param name="property">person</param>
        </generator>

  </id>
  <property name="name"></property>

<!-- 下面的属性lazy="proxy"表示懒加载   fetch="join"表示不懒加载-->
  <one-to-one cascade="all"   name="person"

constrained="true"></one-to-one>
 
 <!-- 第二种写法
 <class name="IdCard">
  <id name="id">
   
        <generator class="native"></generator>

  </id>
  <property name="name"></property>
  <many-to-one name="person" column="person_Id" unique="true" not-

null="true"></many-to-one>-->
 </class>
 
</hibernate-mapping>

 

//Person.hbm.xml的代码

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
 package="com.totalOne2one">
  <class name="Person">
  <id name="personId">
   <generator class="native"></generator>
  </id>
  <component name="name">
   <property name="firstName"></property>
   <property name="lastName"></property>
  </component>
  <one-to-one cascade="all"  name="idCard"></one-to-one>
  
 </class>

 <!-- 第二种写法
 <class name="Person">
  <id name="personId">
   <generator class="native"></generator>
  </id>
  <component name="name">组件映射 
   <property name="firstName"></property>
   <property name="lastName"></property>
  </component>
  <one-to-one cascade="all"  name="idCard"  property-ref="person"/>--><!-- 这就是IdCard中的person，根据它找得到IdCard的对象 -->

</hibernate-mapping>

 

//这是pojos类

public class IdCard {
 
 private Integer id;
 private String name;
 private Person person;
 public Integer getId() {
  return id;
 }
 public void setId(Integer id) {
  this.id = id;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public Person getPerson() {
  return person;
 }
 public void setPerson(Person person) {
  this.person = person;
 }

}

public class Person {
 
 private Integer personId;
 private Name name;
 private IdCard idCard;
 public Integer getPersonId() {
  return personId;
 }
 public void setPersonId(Integer personId) {
  this.personId = personId;
 }
 
 public IdCard getIdCard() {
  return idCard;
 }
 public void setIdCard(IdCard idCard) {
  this.idCard = idCard;
 }
 public Name getName() {
  return name;
 }
 public void setName(Name name) {
  this.name = name;
 }

}

 

public class Name {
 
 private String firstName;
 private String lastName;
 public String getFirstName() {
  return firstName;
 }
 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }
 public String getLastName() {
  return lastName;
 }
 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

}

 

 

//测试的代码

import com.total.HibernateUtil;

public class Main {
 
 
 public static void main(String[] args) {
  
  Session session = HibernateUtil.getSession();
  Transaction transaction = session.beginTransaction();
  /*IdCard idCard = new IdCard();
  idCard.setName("12345");
  Person person = new Person();
  Name name = new Name();
  name.setFirstName("firstname");
  name.setLastName("lastName");
  person.setName(name);
  person.setIdCard(idCard);
  idCard.setPerson(person);
  session.save(person);
  //session.save(idCard);
  transaction.commit();
//  Person person1 = (Person) session.get(Person.class, 1);
//  System.out.println(person1.getIdCard().getName());*/
  //Person person = (Person) session.get(Person.class, 1);
  //System.out.println(person.getIdCard().getName());
  IdCard card  = (IdCard) session.get(IdCard.class, 1);
  Hibernate.initialize(card.getPerson());
  System.out.println("----------");
  System.out.println(card.getPerson().getName());
  session.close();
 }

}