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 [Hibernate]hibernate一对一例子-已更新（一）
软件技术
lhwork 发表于 2007/1/7 14:03:26 |
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先看由满江红翻译团队(RedSaga Translate Team)翻译的一对一配置说明一对一
持久化对象之间一对一的关联关系是通过one-to-one元素定义的。
<one-to-one name="propertyName" (1) class="ClassName" (2) cascade="cascade_style" (3) constrained="true|false" (4) fetch="join|select" (5) property-ref="propertyNameFromAssociatedClass" (6) access="field|property|ClassName" (7) formula="any SQL expression" (8) lazy="true|proxy|false" (9) entity-name="EntityName" (10) node="element-name|@attribute-name|element/@attribute|." embed-xml="true|false"/>
(1)
name: 属性的名字。
(2)
class (可选 - 默认是通过反射得到的属性类型)：被关联的类的名字。
(3)
cascade(级联) (可选) 表明操作是否从父对象级联到被关联的对象。
(4)
constrained(约束) (可选) 表明该类对应的表对应的数据库表，和被关联的对象所对应的数据库表之间，通过一个外键引用对主键进行约束。 这个选项影响save()和delete()在级联执行时的先后顺序以及 决定该关联能否被委托(也在schema export tool中被使用).
(5)
fetch (可选 - 默认设置为选择): 在外连接抓取或者序列选择抓取选择其一.
(6)
property-ref: (可选) 指定关联类的属性名，这个属性将会和本类的主键相对应。如果没有指定，会使用对方关联类的主键。
(7)
access (可选 - 默认是 property): Hibernate用来访问属性的策略。
(8)
formula (可选):绝大多数一对一的关联都指向其实体的主键。在一些少见的情况中， 你可能会指向其他的一个或多个字段，或者是一个表达式，这些情况下，你可以用一个SQL公式来表示。 （可以在org.hibernate.test.onetooneformula找到例子）
(9)
lazy (可选 - 默认为 proxy): 默认情况下，单点关联是经过代理的。lazy="true"指定此属性应该在实例变量第一次被访问时应该延迟抓取（fetche lazily）（需要运行时字节码的增强）。 lazy="false"指定此关联总是被预先抓取。注意，如果constrained="false", 不可能使用代理，Hibernate会采取预先抓取！
(10)
entity-name (可选): 被关联的类的实体名。
具体配置可以看http://www.huihoo.com/framework/hibernate/reference-v3_zh-cn/mapping.html好。。再来测试。。。1.建表
500)this.width=500'>
create
table
student500)this.width=500'>(sid
varchar
(
32
)
not
null
primary
key
,500)this.width=500'> sname
varchar
(
16
),500)this.width=500'> sage
varchar
(
16
)500)this.width=500'>)500)this.width=500'>
create
table
address500)this.width=500'>(aid
varchar
(
32
)
not
null
primary
key
,500)this.width=500'>acity
varchar
(
16
),500)this.width=500'>aroad
varchar
(
16
)500)this.width=500'>)500)this.width=500'>
2.写VO Address vo500)this.width=500'>package com.test;500)this.width=500'>500)this.width=500'>public class Address500)this.width=500'>500)this.width=500'>500)this.width=500'>{500)this.width=500'> private String aid;500)this.width=500'> private String acity;500)this.width=500'> private String aroad;500)this.width=500'> private Student student;500)this.width=500'> //写上GET SET方法500)this.width=500'>Student vo500)this.width=500'>package com.test;500)this.width=500'>public class Student500)this.width=500'>500)this.width=500'>500)this.width=500'>{500)this.width=500'> private String sid;500)this.width=500'> private String sname;500)this.width=500'> private String sage;500)this.width=500'> private Address address;500)this.width=500'>//写上get set3.写配置文件Student.hbm.xml500)this.width=500'><?xml version="1.0"?>500)this.width=500'><!DOCTYPE hibernate-mapping500)this.width=500'> PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"500)this.width=500'> "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">500)this.width=500'>500)this.width=500'><hibernate-mapping>500)this.width=500'>500)this.width=500'> <class name="com.test.Student" table="student" >500)this.width=500'>500)this.width=500'> <id name="sid" type="string" unsaved-value="null" >500)this.width=500'> <column name="sid" sql-type="char(32)" not-null="true"/>500)this.width=500'> <generator class="uuid.hex"/>500)this.width=500'> </id>500)this.width=500'>500)this.width=500'> <property name="sname">500)this.width=500'> <column name="sname" sql-type="varchar(16)" />500)this.width=500'> </property>500)this.width=500'>500)this.width=500'> <property name="sage">500)this.width=500'> <column name="sage" sql-type="varchar(16)" />500)this.width=500'> </property>500)this.width=500'>500)this.width=500'> <one-to-one name="address" class="com.test.Address" cascade="all"/> 500)this.width=500'> 500)this.width=500'> </class>500)this.width=500'>500)this.width=500'></hibernate-mapping>Address.hbm.xml500)this.width=500'><?xml version="1.0"?>500)this.width=500'><!DOCTYPE hibernate-mapping500)this.width=500'> PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"500)this.width=500'> "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">500)this.width=500'>500)this.width=500'><hibernate-mapping>500)this.width=500'>500)this.width=500'> <class name="com.test.Address" table="address" >500)this.width=500'>500)this.width=500'> <id name="aid" type="string" unsaved-value="null" >500)this.width=500'> <column name="aid" sql-type="char(32)" not-null="true"/>500)this.width=500'> <generator class="foreign">500)this.width=500'> <param name="property">student</param>500)this.width=500'> </generator>500)this.width=500'> </id>500)this.width=500'>500)this.width=500'> <property name="acity">500)this.width=500'> <column name="acity" sql-type="varchar(16)" />500)this.width=500'> </property>500)this.width=500'>500)this.width=500'> <property name="aroad">500)this.width=500'> <column name="aroad" sql-type="varchar(16)" />500)this.width=500'> </property>500)this.width=500'>500)this.width=500'> <one-to-one name="student" class="com.test.Student"/>500)this.width=500'>500)this.width=500'> </class>500)this.width=500'>500)this.width=500'></hibernate-mapping>接着把下面的hibernate.properties文件拷到classes目录下。。这里用的是mysql500)this.width=500'>hibernate.query.substitutions true 1, false 0, yes 'Y', no 'N'500)this.width=500'>## MySQL500)this.width=500'>hibernate.dialect net.sf.hibernate.dialect.MySQLDialect500)this.width=500'>hibernate.connection.driver_class org.gjt.mm.mysql.Driver500)this.width=500'>hibernate.connection.url jdbc:mysql://localhost:3306/wjcms500)this.width=500'>hibernate.connection.username root500)this.width=500'>hibernate.connection.password wujun500)this.width=500'>hibernate.connection.pool_size 1500)this.width=500'>hibernate.proxool.pool_alias pool1500)this.width=500'>hibernate.show_sql true500)this.width=500'>hibernate.jdbc.batch_size 0500)this.width=500'>hibernate.max_fetch_depth 1500)this.width=500'>hibernate.cache.use_query_cache true 4.写测试类了..500)this.width=500'>package com.test;500)this.width=500'>500)this.width=500'>import net.sf.hibernate.Session;500)this.width=500'>import net.sf.hibernate.SessionFactory;500)this.width=500'>import net.sf.hibernate.cfg.Configuration;500)this.width=500'>import net.sf.hibernate.*;500)this.width=500'>import java.sql.*;500)this.width=500'>import java.util.List;500)this.width=500'>500)this.width=500'>public class TestOneToOne500)this.width=500'>500)this.width=500'>500)this.width=500'>{500)this.width=500'> SessionFactory sf;500)this.width=500'> Session session;500)this.width=500'> public TestOneToOne()500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> try500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> Configuration cfg = new Configuration();500)this.width=500'> sf = cfg.addClass(Student.class).addClass(Address.class).buildSessionFactory();500)this.width=500'> }500)this.width=500'> catch(HibernateException ex)500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> ex.printStackTrace();500)this.width=500'> }500)this.width=500'> }500)this.width=500'> public void doCreate()500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> try500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> session = sf.openSession();500)this.width=500'>500)this.width=500'> Student student = new Student();500)this.width=500'> student.setSname("小王");500)this.width=500'> student.setSage("22");500)this.width=500'>500)this.width=500'> Address address = new Address();500)this.width=500'> address.setAcity("深圳");500)this.width=500'> address.setAroad("深南");500)this.width=500'> address.setStudent(student);500)this.width=500'> student.setAddress(address);500)this.width=500'>500)this.width=500'> session.save(student);500)this.width=500'> session.flush();500)this.width=500'> session.connection().commit();500)this.width=500'>500)this.width=500'> }500)this.width=500'> catch(HibernateException ex)500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> ex.printStackTrace();500)this.width=500'> }500)this.width=500'> catch(SQLException ex1)500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> ex1.printStackTrace();500)this.width=500'> }500)this.width=500'> finally500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'>500)this.width=500'> try500)this.width=500'>{500)this.width=500'> session.close();500)this.width=500'> }500)this.width=500'>500)this.width=500'> catch(HibernateException ex2)500)this.width=500'>{500)this.width=500'> }500)this.width=500'> }500)this.width=500'>500)this.width=500'> }500)this.width=500'> public void doQuery()500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'>500)this.width=500'> try500)this.width=500'>{500)this.width=500'> session = sf.openSession();500)this.width=500'> Query q = session.createQuery("select s from Student as s");500)this.width=500'> List l = q.list();500)this.width=500'> Student s = null;500)this.width=500'> Address address = null;500)this.width=500'> for(int i=0;i<l.size();i++)500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> s = (Student)l.get(i);500)this.width=500'> System.out.println("姓名： "+s.getSname());500)this.width=500'> System.out.println("年龄： "+s.getSage());500)this.width=500'> address = s.getAddress();500)this.width=500'> System.out.println("住址: "+address.getAcity()+address.getAroad());500)this.width=500'> }500)this.width=500'>500)this.width=500'> }500)this.width=500'>500)this.width=500'> catch(HibernateException ex)500)this.width=500'>{500)this.width=500'> ex.printStackTrace();500)this.width=500'> }500)this.width=500'>500)this.width=500'> finally500)this.width=500'>{500)this.width=500'>500)this.width=500'> try500)this.width=500'>{500)this.width=500'> session.close();500)this.width=500'> }500)this.width=500'>500)this.width=500'> catch(HibernateException ex2)500)this.width=500'>{500)this.width=500'> }500)this.width=500'> }500)this.width=500'> }500)this.width=500'> public static void main(String[] args)500)this.width=500'>500)this.width=500'> 500)this.width=500'>{500)this.width=500'> TestOneToOne t = new TestOneToOne();500)this.width=500'> //t.doCreate();500)this.width=500'> t.doQuery();500)this.width=500'> }500)this.width=500'>}500)this.width=500'>
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回复:hibernate一对一例子-已更新（一）
软件技术
geniusloci(游客)发表评论于2008/3/25 14:05:59 |
| 请问在student.hbm.xml中
<generator class="uuid.hex">
是什么原理? |
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