一 概念介绍
一对一的方式有两种，分为：
（1）基于主键的方式 --- 共用主键(Person --- IdCard)典型的一对一
没有增加额外的列
（2）基于外键的方式 --- 增加额外的一列
下面介绍一下第一中基于主键的实现
二 代码分析
（1）Person类
package com.hbsi.domain;
public class Person {
private int id;
private String name;
private IdCard idCard;//一个人对应一个IdCard
public Person() {
super();
// TODO Auto-generated constructor stub
}
public Person(int id, String name, IdCard idCard) {
super();
this.id = id;
this.name = name;
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 IdCard getIdCard() {
return idCard;
}
public void setIdCard(IdCard idCard) {
this.idCard = idCard;
}
public String toString() {
return "Person [id=" + id + ", name=" + name + ", idCard=" + idCard
+ "]";
}
}
（2）IdCard类
package com.hbsi.domain;
import java.util.Date;
public class IdCard {
private int id;
private Date usefulLife;
private Person person; //一个IdCard只属于一个人
public IdCard() {
super();
// TODO Auto-generated constructor stub
}
public IdCard(int id, Date usefulLife, Person person) {
super();
this.id = id;
this.usefulLife = usefulLife;
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;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
}
（3）在配置文件中配置Person类和IdCard类
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
"hibernate.connection.driver_class">com.mysql.jdbc.Driver
"hibernate.connection.url">jdbc:mysql:///demo
"hibernate.connection.username">root
"hibernate.connection.password">1234
"hibernate.dialect">org.hibernate.dialect.MySQLDialect
"hibernate.hbm2ddl.auto">update
"hibernate.show_sql">true
"com/hbsi/domain/Person.hbm.xml" />
"com/hbsi/domain/IdCard.hbm.xml" />