Hibernate学习（二）---【一对一唯一外键单向关联】

Hibernate学习（二）---【一对一唯一外键单向关联】

一对一外键关联其实就是多对多特例。
person.java

package  com.zzn.hibernate.OneToOne;

public   class  Person {
     private   int  id;
     private  String name;
     private   int  age;
     private  IdCard idCard;
     public  IdCard getIdCard() {
         return  idCard;
    }
     public   void  setIdCard(IdCard idCard) {
         this .idCard  =  idCard;
    }
     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   int  getAge() {
         return  age;
    }
     public   void  setAge( int  age) {
         this .age  =  age;
    }
    
}

IdCard.java

package  com.zzn.hibernate.OneToOne;

public   class  IdCard {
     private   int  id;
     private  String cardNo;
     public   int  getId() {
         return  id;
    }
     public   void  setId( int  id) {
         this .id  =  id;
    }
     public  String getCardNo() {
         return  cardNo;
    }
     public   void  setCardNo(String cardNo) {
         this .cardNo  =  cardNo;
    }
    
}

Person.hbm.xml

<? 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 >
     < class  name ="com.zzn.hibernate.OneToOne.Person"  table ="PERSON" >
         < id  name ="id"  column ="id" >
             < generator  class ="native"   />
         </ id >
         < property  name ="name"   />
         < property  name ="age"   />
         <!--  也就是在person表中加入一个外键idCard，设置unique="ture"就变成一对一了;  
         cascade="all"必须加上这样两表才能关联，操作person时，Idcard也随之改变 -->
         < many-to-one  name ="idCard"  unique ="true"  cascade ="all" />
     </ class >
</ hibernate-mapping >

IdCard.hbm.xml

<? 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 >
     < class  name ="com.zzn.hibernate.OneToOne.IdCard"  table ="ID_CARD" >
         < id  name ="id"  column ="id" >
             < generator  class ="native"   />
         </ id >
         < property  name ="cardNo"   />
     </ class >
</ hibernate-mapping >

test.java

public   class  OneToOne_pk2  extends  TestCase {
     public   void  OneToOne_pk2_1() {
        Session session  =   null ;
        Transaction tx  =   null ;
         try  {
            session  =  HibernateUtils.getSession();
            tx  =  session.beginTransaction();
            IdCard idCard  =   new  IdCard();
            Person person  =   new  Person();

            idCard.setCardNo( " 222222 " );
            person.setName( " 刘德华 " );
            person.setAge( 50 );
            person.setIdCard(idCard);
            session.save(person);
            
            System.out.println( " person's name =  "   +  person.getName());
            System.out.println( " idCard's cardNo =  "
                     +  person.getIdCard().getCardNo());
            
        }  catch  (Exception e) {
            e.printStackTrace();
        }  finally  {
             if  (session  !=   null ) {
                 if  (session.isOpen()) {
                    tx.commit();
                    session.close();
                }
            }
        }
    }
    
     public   void  OneToOne_pk2_2() {
        Session session  =   null ;
        Transaction tx  =   null ;
         try  {
            session  =  HibernateUtils.getSession();
            tx  =  session.beginTransaction();
             for  ( int  i = 1  ;i <= 2 ;i ++ ){
            Person person  =  (Person)session.load(Person. class , i);
            System.out.println( " person's name =  "   +  person.getName());
            System.out.println( " idCard's cardNo =  "
                     +  person.getIdCard().getCardNo());
            }
        }  catch  (Exception e) {
            e.printStackTrace();
        }  finally  {
             if  (session  !=   null ) {
                 if  (session.isOpen()) {
                    tx.commit();
                    session.close();
                }
            }
        }
    }
}