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hibernate一對一例子-已更新（一）

先看由滿江紅翻譯團隊(RedSaga Translate Team)翻譯的一對一配置說明
一對一

持久化對象之間一對一的關聯關系是通過one-to-one元素定義的。

<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`: 屬性的名字。
(2)	`class` (可選 - 默認是通過反射得到的屬性類型)：被關聯的類的名字。
(3)	`cascade(級聯)` (可選) 表明操作是否從父對象級聯到被關聯的對象。
(4)	`constrained(約束)` (可選) 表明該類對應的表對應的數據庫表，和被關聯的對象所對應的數據庫表之間，通過一個外鍵引用對主鍵進行約束。這個選項影響`save()`和`delete()`在級聯執行時的先后順序以及決定該關聯能否被委托(也在schema export tool中被使用).
(5)	`fetch` (可選 - 默認設置為`選擇`): 在外連接抓取或者序列選擇抓取選擇其一.
(6)	`property-ref`: (可選) 指定關聯類的屬性名，這個屬性將會和本類的主鍵相對應。如果沒有指定，會使用對方關聯類的主鍵。
(7)	`access` (可選 - 默認是 `property`): Hibernate用來訪問屬性的策略。
(8)	`formula` (可選):絕大多數一對一的關聯都指向其實體的主鍵。在一些少見的情況中，你可能會指向其他的一個或多個字段，或者是一個表達式，這些情況下，你可以用一個SQL公式來表示。（可以在org.hibernate.test.onetooneformula找到例子）
(9)	`lazy` (可選 - 默認為 `proxy`): 默認情況下，單點關聯是經過代理的。`lazy="true"`指定此屬性應該在實例變量第一次被訪問時應該延遲抓?。╢etche lazily）（需要運行時字節碼的增強）。 `lazy="false"`指定此關聯總是被預先抓取。注意，如果`constrained="false"`, 不可能使用代理，Hibernate會采取預先抓取！
(10)	`entity-name` (可選): 被關聯的類的實體名。

具體配置可以看
http://www.huihoo.com/framework/hibernate/reference-v3_zh-cn/mapping.html
好。。再來測試。。。
1.建表

create ? table ?student

(sid? varchar ( 32 )? not ? null ? primary ? key ,

?sname? varchar ( 16 ),

?sage? varchar ( 16 )

)

create ? table ?address

(aid? varchar ( 32 )? not ? null ? primary ? key ,

acity? varchar ( 16 ),

aroad? varchar ( 16 )

)

2.寫VO
?? Address vo

package?com.test;

public?class?Address

{

????private?String?aid;

????private?String?acity;

????private?String?aroad;

????private?Student?student;

??//寫上GET?SET方法

Student vo

package?com.test;

public?class?Student

{

????private?String?sid;

????private?String?sname;

????private?String?sage;

????private?Address?address;

//寫上get?set

3.寫配置文件
Student.hbm.xml

<?xml?version="1.0"?>

<!DOCTYPE?hibernate-mapping

????PUBLIC?"-//Hibernate/Hibernate?Mapping?DTD//EN"

????"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>

????<class?name="com.test.Student"?table="student"?>

????????<id?name="sid"?type="string"?unsaved-value="null"?>

????????????<column?name="sid"?sql-type="char(32)"?not-null="true"/>

????????????<generator?class="uuid.hex"/>

????????</id>

????????<property?name="sname">

????????????<column?name="sname"?sql-type="varchar(16)"?/>

????????</property>

????????<property?name="sage">

????????????<column?name="sage"?sql-type="varchar(16)"?/>

????????</property>

????????<one-to-one?name="address"?class="com.test.Address"?cascade="all"/>?

???

????</class>

</hibernate-mapping>

Address.hbm.xml

<?xml?version="1.0"?>

<!DOCTYPE?hibernate-mapping

????PUBLIC?"-//Hibernate/Hibernate?Mapping?DTD//EN"

????"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>

????<class?name="com.test.Address"?table="address"?>

????????<id?name="aid"?type="string"?unsaved-value="null"?>

????????????<column?name="aid"?sql-type="char(32)"?not-null="true"/>

????????????<generator?class="foreign">

????????????????<param?name="property">student</param>

????????????</generator>

????????</id>

????????<property?name="acity">

????????????<column?name="acity"?sql-type="varchar(16)"?/>

????????</property>

????????<property?name="aroad">

????????????<column?name="aroad"?sql-type="varchar(16)"?/>

????????</property>

????????<one-to-one?name="student"?class="com.test.Student"/>

????</class>

</hibernate-mapping>

接著把下面的hibernate.properties文件拷到classes目錄下。。這里用的是mysql

hibernate.query.substitutions?true?1,?false?0,?yes?'Y',?no?'N'

##?MySQL

hibernate.dialect?net.sf.hibernate.dialect.MySQLDialect

hibernate.connection.driver_class?org.gjt.mm.mysql.Driver

hibernate.connection.url?jdbc:mysql://localhost:3306/wjcms

hibernate.connection.username?root

hibernate.connection.password?wujun

hibernate.connection.pool_size?1

hibernate.proxool.pool_alias?pool1

hibernate.show_sql?true

hibernate.jdbc.batch_size?0

hibernate.max_fetch_depth?1

hibernate.cache.use_query_cache?true?

4.寫測試類了..

package?com.test;

import?net.sf.hibernate.Session;

import?net.sf.hibernate.SessionFactory;

import?net.sf.hibernate.cfg.Configuration;

import?net.sf.hibernate.*;

import?java.sql.*;

import?java.util.List;

public?class?TestOneToOne

{

????SessionFactory?sf;

????Session?session;

????public?TestOneToOne()

????{

????????try

????????{

????????????Configuration?cfg?=?new?Configuration();

????????????sf?=?cfg.addClass(Student.class).addClass(Address.class).buildSessionFactory();

????????}

????????catch(HibernateException?ex)

????????{

????????????ex.printStackTrace();

????????}

????}

????public?void?doCreate()

????{

????????try

????????{

????????????session?=?sf.openSession();

????????????Student?student?=?new?Student();

????????????student.setSname("小王");

????????????student.setSage("22");

????????????Address?address?=?new?Address();

????????????address.setAcity("深圳");

????????????address.setAroad("深南");

????????????address.setStudent(student);

????????????student.setAddress(address);

????????????session.save(student);

????????????session.flush();

????????????session.connection().commit();

????????}

????????catch(HibernateException?ex)

????????{

????????????ex.printStackTrace();

????????}

????????catch(SQLException?ex1)

????????{

????????????ex1.printStackTrace();

????????}

????????finally

????????{

????????????????try{

????????????????????session.close();

????????????????}

????????????????catch(HibernateException?ex2){

????????????????}

????????}

????}

????public?void?doQuery()

????{

????????try{

????????????session?=?sf.openSession();

????????????Query?q?=?session.createQuery("select?s?from?Student?as?s");

????????????List?l?=?q.list();

????????????Student?s?=?null;

????????????Address?address?=?null;

????????????for(int?i=0;i<l.size();i++)

????????????{

????????????????s?=?(Student)l.get(i);

????????????????System.out.println("姓名：?"+s.getSname());

????????????????System.out.println("年齡：?"+s.getSage());

????????????????address?=?s.getAddress();

????????????????System.out.println("住址:??"+address.getAcity()+address.getAroad());

????????????}

????????}

????????catch(HibernateException?ex){

????????????ex.printStackTrace();

????????}

????????finally{

????????????try{

????????????????session.close();

????????????}

????????????catch(HibernateException?ex2){

????????????}

????????}

????}

????public?static?void?main(String[]?args)

????{

????????TestOneToOne?t?=?new?TestOneToOne();

????????//t.doCreate();

????????t.doQuery();

????}

}

posted on 2006-04-06 16:05 record java and net 閱讀(6057) 評論(3) 編輯收藏所屬分類: java


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# re: hibernate一對一例子-方便以后查看（一） 2006-04-13 11:45 foreverjiang

# re: hibernate一對一例子-已更新（一） 2006-04-22 09:50 吳某人-不斷地學習

# re: hibernate一對一例子-已更新（一） 2008-04-29 10:52 xx

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