Hibernate关系映射一对一

Hibernate关系映射一对一

1. 一对一，比如一个表的字段有100多个，而且其中有40个其他表可能有用，那么你把这个表拆分成两个表，并且两个表中的数据都是一条记录对应一条记录，某一个表中存放另一个对应表的id用来维护两个记录之间的关系，因为本来这两条记录原来就是一条记录，不知道这么说你能明白吗？再比如：人和身份证

2. 身份证IdCard类：

public class IdCard {
private int id;
private Date usefulLife;
private Person person;

public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Date getUsefulLife() {
return usefulLife;
}
public void setUsefulLife(Date usefulLife) {
this.usefulLife = usefulLife;
}
3. Person类：

public class Person {
private int id;
private String name;
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;
}

4. 映射文件：

IdCard

<hibernate-mapping
package="com.hbsi.domain">

<class name="IdCard" table="id_card">
<id name="id"column="id">
<generator class="foreign">
<param name="property">person</param>
</generator>
</id>
<property name="usefulLife"column="userful_life"/>
<one-to-one name="person"></one-to-one>
</class>

</hibernate-mapping>

Person映射文件

<hibernate-mapping
package="com.hbsi.domain">

<class name="IdCard" table="id_card">
<id name="id"column="id">
<generator class="foreign">
<param name="property">person</param>
</generator>
</id>
<property name="usefulLife"column="userful_life"/>
<one-to-one name="person"></one-to-one>
</class>

</hibernate-mapping>

5．测试类

public static void main(String[] args) {
// TODO Auto-generatedmethod stub
add();

}
static Person add(){
Session s=null;
Transaction tx=null;
try{
s= HibernateUtil.getSession();
tx=s.beginTransaction();
//增加
IdCard idCard=new IdCard();
idCard.setUsefulLife(new Date());

Person p=new Person();
p.setName("ds");
p.setIdCard(idCard);
//
idCard.setPerson(p);

s.save(p);
s.save(idCard);

tx.commit();
return p;

}finally{
if(s!=null)
s.close();
}
}

static Person queryq1(int perId){
Session s=null;
Transaction tx=null;
try{
s= HibernateUtil.getSession();
tx=s.beginTransaction();
Person d= (Person) s.get(Person.class, perId);
System.out.println(d.getName());

tx.commit();
return d;

}finally{
if(s!=null)
s.close();
}

}