Hibernate一对一关系代码实例-hibernate query

一对一的关系在数据库中表示为主外关系．在Hibernate中的一对一关系通过映射实现。例如．人和身份证的关系．每个人都对应一个身份证号．我们应该两个表．一个是关于人信息的表(user)．别外一个是身份证相关信息的表(card)．card表的主键对应该user表的主键userid，也是user表的外键．有人才能有身份证．

Users表

    CREATE TABLE `users` (
`user_id` int(11) NOT NULL auto_increment,
`user_name` varchar(20) default NULL,
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;

Card 表

    CREATE TABLE `card` (
`card_id` int(11) NOT NULL auto_increment,
`card_no` varchar(20) default NULL,
`user_id` int(11) default NULL,
PRIMARY KEY (`card_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;

JAVA 代码

Users 类

    package org.yy.hbn.pojo;

public class Users implements java.io.Serializable {
private Integer userId;
private String userName;
private Card card; //Users对象中存一个Card 对象
public Users() {
}
public Users(String userName) {
this.userName = userName;
}
public Integer getUserId() {
return this.userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getUserName() {
return this.userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public Card getCard() {
return card;
}
public void setCard(Card card) {
this.card = card;
}
public Users(Integer userId, String userName, Card card) {
super();
this.userId = userId;
this.userName = userName;
this.card = card;
}
}

Card 类

   package org.yy.hbn.pojo;
public class Card implements java.io.Serializable {
private Integer cardId;
private String cardNo;
private Users users; //Card对象中存一个Users 对象
public Card(Integer cardId, String cardNo, Users users) {
super();
this.cardId = cardId;
this.cardNo = cardNo;
this.users = users;
}
public Card() {
}
public Integer getCardId() {
return this.cardId;
}
public void setCardId(Integer cardId) {
this.cardId = cardId;
}
public String getCardNo() {
return this.cardNo;
}
public void setCardNo(String cardNo) {
this.cardNo = cardNo;
}

public Users getUsers() {
return users;
}
public void setUsers(Users users) {
this.users = users;
}
}

XML 代码

Card.hbn.xml

    
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

Users.hbn.xml

   
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

hibernate.cfg.xml 代码

   
 "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">


root

jdbc:mysql://localhost:3306/test


org.hibernate.dialect.MySQLDialect

mysql

com.mysql.jdbc.Driver

true

JAVA 测试代码

    package org.yy.hbn.test;
import org.hibernate.Transaction;
import org.hibernate.Session;
import org.yy.hbn.HibernateSessionFactory;
import org.yy.hbn.pojo.Card;
import org.yy.hbn.pojo.Users;
public class test {
public static void main(String[] args) {
select();
}
private static void add()
{
Session session=HibernateSessionFactory.getSession();
Transaction tran=session.beginTransaction();
try {
Users user=new Users();
user.setUserName("UU");
Card card=new Card();
card.setCardNo("89012345");
//卡跟用户建立关系
card.setUsers(user);
//用户也跟卡建立关系
user.setCard(card);
session.save(user);
tran.commit();
} catch (Exception e) {
 e.printStackTrace();
 tran.rollback();
}finally{
 HibernateSessionFactory.closeSession();
}  
}

private static void select()
{
Session session=HibernateSessionFactory.getSession();
//查找用户信息，可以通过用户来找到对应的卡的信息
Users user=(Users)session.get(Users.class,new Integer(1));
System.out.println(user.getUserName());
System.out.println(user.getCard().getCardNo());

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