Action 3 Spring Integrating Hibernate

刚好十一期间 Spring2.0的中文reference出来了 所以把这部分总结实践一下

一 资源管理

DataSource sessionFactory的组装

beans-config.xml

<? xmlversion="1.0"encoding="UTF-8" ?>
<! DOCTYPEbeansPUBLIC"-//SPRING//DTDBEAN//EN""http://www.springframework.org/dtd/spring-beans.dtd" >

< beans >

<!-- =================================================================== -->
<!-- JDBCdataSource -->
<!-- =================================================================== -->

<!-- ***********************************************************************
<beanid="dataSource"class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<propertyname="driverClassName">
<value>com.mysql.jdbc.Driver</value>
</property>
<propertyname="url">
<value>jdbc:mysql://localhost:3306/shtest</value>
</property>
<propertyname="username">
<value>root</value>
</property>
<propertyname="password">
<value>72001234</value>
</property>
</bean>
************************************************************************ -->

<!-- =================================================================== -->
<!-- c3p0dataSource -->
<!-- =================================================================== -->


< bean id ="dataSource" class ="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method ="close" >
< property name ="driverClass" >
< value > com.mysql.jdbc.Driver </ value >
</ property >
< property name ="jdbcUrl" >
< value > jdbc:mysql://localhost:3306/shtest </ value >
</ property >
< property name ="properties" >
< props >
< prop key ="c3p0.acquire_increment" > 2 </ prop >
< prop key ="c3p0.idle_test_period" > 200 </ prop >
< prop key ="c3p0.timeout" > 1000 </ prop >
< prop key ="c3p0.max_size" > 100 </ prop >
< prop key ="hibernate.c3p0.max_statements" > 100 </ prop >
< prop key ="hibernate.c3p0.min_size" > 20 </ prop >
< prop key ="user" > root </ prop >
< prop key ="password" > 72001234 </ prop >
</ props >
</ property >
</ bean >


<!-- =================================================================== -->
<!-- HibernatesessionFactory -->
<!-- =================================================================== -->

< bean id ="sessionFactory" class ="org.springframework.orm.hibernate3.LocalSessionFactoryBean" destroy-method ="close" >
< property name ="dataSource" >
< ref bean ="dataSource" />
</ property >
< property name ="mappingResources" >
< list >
< value > /com/ergal/hibernate/User.hbm.xml </ value >
</ list >
</ property >
< property name ="hibernateProperties" >
< props >
< prop key ="hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ prop >
< prop key ="hibernate.show_sql" > true </ prop >
< prop key ="hibernate.current_session_context_class" > thread </ prop >
</ props >
</ property >
</ bean >

<!-- =================================================================== -->
<!-- HibernatePOJO -->
<!-- =================================================================== -->

< bean id ="userDao" class ="com.ergal.hibernate.UserDao" >
< property name ="sessionFactory" >
< ref bean ="sessionFactory" />
</ property >
</ bean >

<!-- =================================================================== -->
<!-- transactionManager -->
<!-- =================================================================== -->

< bean id ="transactionManager" class ="org.springframework.orm.hibernate3.HibernateTransactionManager" >
< property name ="sessionFactory" >
< ref bean ="sessionFactory" />
</ property >
</ bean >

<!-- =================================================================== -->
<!-- DaoProxy -->
<!-- =================================================================== -->

< bean id ="userDaoProxy" class ="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" >
< property name ="transactionManager" >
< ref bean ="transactionManager" />
</ property >
< property name ="proxyInterfaces" >
< list >
< value > com.ergal.hibernate.IUserDao </ value >
</ list >
</ property >
< property name ="target" >
< ref bean ="userDao" />
</ property >
< property name ="transactionAttributes" >
< props >
< prop key ="insert" > PROPAGATION_REQUIRED </ prop >
</ props >
</ property >

</ bean >

</ beans >

也可以直接使用JNDI资源

< beans >

< bean id ="myDataSource" class ="org.springframework.jndi.JndiObjectFactoryBean" >
< property name ="jndiName" value ="java:comp/env/jdbc/myds" />
</ bean >

...
</ beans >

二 HibernateTemplate

HibernateTemplate上有一些方便的方法可以自动建立callback对象 一些方法get() save() delete() 等等

在不使用代理的情况下

UserDao变的比较灵活

比如按名字查询的方法可以写成

package com.ergal.hibernate;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.springframework.orm.hibernate3.HibernateTemplate;

public class UserDao implements IUserDao
... {
privateHibernateTemplatehibernateTemplate;

publicUserDao()...{}
/**//*
publicUserDao(SessionFactorysessionFactory)
{
this.sessionFactory=sessionFactory;
}*/

publicvoidsetSessionFactory(SessionFactorysessionFactory)
...{
hibernateTemplate=newHibernateTemplate(sessionFactory);
}



publicvoidinsert(Useruser)
...{
hibernateTemplate.save(user);
//TODOAuto-generatedmethodstub
/**//*Sessionsession=sessionFactory.openSession();
Transactiontx=session.beginTransaction();
session.save(user);
tx.commit();
session.close();*/
}

publicStringgetPassword(Stringusername)
...{
/**//*
Sessionsession=sessionFactory.openSession();
Transactiontx=session.beginTransaction();
Listresult=session.createQuery("fromUseruwhereusername=:name").setString("name",username).list();
Stringpassword=null;
for(Iteratorit=result.iterator();it.hasNext();)
{
Useru=(User)it.next();
Hibernate.initialize(u.getPassword());
password=(String)u.getPassword();
}
tx.commit();
session.close();
returnpassword;
*/

Listresult=hibernateTemplate.find("fromUseruwhereusername=?",username);
Stringpassword=null;
for(Iteratorit=result.iterator();it.hasNext();)
...{
Useru=(User)it.next();
Hibernate.initialize(u.getPassword());
password=(String)u.getPassword();
}
returnpassword;
}

}

也可以写成

SessionFactorysf = hibernateTemplate.getSessionFactory();
Sessionsession = sf.openSession();
Transactiontx = session.beginTransaction();
Listresult = session.createQuery( " fromUseruwhereusername=:name " ).setString( " name " ,username).list();
Stringpassword = null ;
for (Iteratorit = result.iterator();it.hasNext();)
... {
Useru=(User)it.next();
Hibernate.initialize(u.getPassword());
password=(String)u.getPassword();
}
return password;

当然 直接利用hibernateTemplate的方法是比较简洁的

三 HibernateDaoSupport

可以省去一些SessionFactory和HibernateTemplate的管理 只需要注入SessionFactory的实例就可以了

<!-- ======== CONSTRUCTOR SUMMARY ======== --><!-- -->

Constructor Summary

HibernateDaoSupport()

<!-- ========== METHOD SUMMARY =========== --> <!-- --> Method Summary

protected void	checkDaoConfig() Abstract subclasses must override this to check their configuration.
protected void	closeSessionIfNecessary(org.hibernate.Sessionsession) Deprecated.in favor of releaseSession
protected DataAccessException	convertHibernateAccessException(org.hibernate.HibernateExceptionex) Convert the given HibernateException to an appropriate exception from the org.springframework.dao hierarchy.
protected HibernateTemplate	createHibernateTemplate(org.hibernate.SessionFactorysessionFactory) Create a HibernateTemplate for the given SessionFactory.
HibernateTemplate	getHibernateTemplate() Return the HibernateTemplate for this DAO, pre-initialized with the SessionFactory or set explicitly.
protected org.hibernate.Session	getSession() Get a Hibernate Session, either from the current transaction or a new one.
protected org.hibernate.Session	getSession(booleanallowCreate) Get a Hibernate Session, either from the current transaction or a new one.
org.hibernate.SessionFactory	getSessionFactory() Return the Hibernate SessionFactory used by this DAO.
protected void	releaseSession(org.hibernate.Sessionsession) Close the given Hibernate Session, created via this DAO's SessionFactory, if it isn't bound to the thread.
void	setHibernateTemplate(HibernateTemplatehibernateTemplate) Set the HibernateTemplate for this DAO explicitly, as an alternative to specifying a SessionFactory.
void	setSessionFactory(org.hibernate.SessionFactorysessionFactory) Set the Hibernate SessionFactory to be used by this DAO.

<!-- -->

于是可以把代码改成以下来测试一下

package com.ergal.hibernate;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Hibernate;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

public class UserDao extends HibernateDaoSupport implements IUserDao
... {
//privateHibernateTemplatehibernateTemplate;

publicUserDao()...{}
/**//*
publicUserDao(SessionFactorysessionFactory)
{
this.sessionFactory=sessionFactory;
}*/
/**//*
publicvoidsetSessionFactory(SessionFactorysessionFactory)
{
hibernateTemplate=newHibernateTemplate(sessionFactory);
}*/



publicvoidinsert(Useruser)
...{
getHibernateTemplate().save(user);
//TODOAuto-generatedmethodstub
/**//*Sessionsession=sessionFactory.openSession();
Transactiontx=session.beginTransaction();
session.save(user);
tx.commit();
session.close();*/
}

publicStringgetPassword(Stringusername)
...{
/**//*
Sessionsession=sessionFactory.openSession();
Transactiontx=session.beginTransaction();
Listresult=session.createQuery("fromUseruwhereusername=:name").setString("name",username).list();
Stringpassword=null;
for(Iteratorit=result.iterator();it.hasNext();)
{
Useru=(User)it.next();
Hibernate.initialize(u.getPassword());
password=(String)u.getPassword();
}
tx.commit();
session.close();
returnpassword;
*/

Listresult=getHibernateTemplate().find("fromUseruwhereusername=?",username);
Stringpassword=null;
for(Iteratorit=result.iterator();it.hasNext();)
...{
Useru=(User)it.next();

password=(String)u.getPassword();
}
returnpassword;

}

}

这样很多管理就被省去了 包括session sessionFactory

reference上还写了一些关于使用

Hibernate原生API的方法

就是直接自己编写Hibernate的实现方法来实现DAO

如

Sessionsession = sessionFactory.openSession();
Transactiontx = session.beginTransaction();
Listresult = session.createQuery( " fromUseruwhereusername=:name " ).setString( " name " ,username).list();
Stringpassword = null ;
for (Iteratorit = result.iterator();it.hasNext();)
... {
Useru=(User)it.next();
Hibernate.initialize(u.getPassword());
password=(String)u.getPassword();
}
tx.commit();
session.close();
return password;

不使用回调基于DAO的实现

无需将Hibernate访问代码放在一个回调中 只要符合Spring通用的DataAccessException异常体系HibernateDaoSupport提供了访问当前事务绑定的session对象的函数 保证在这种情况下异常的正常转化 (false)作为参数 表示是否允许创建 此时整个调用在一个session中完成（整个生命周期由事务控制 避免了关闭session的需要）

......
Sessionsession = getSession(getSessionFactory, false )
try
... {
Listresult=session.createQuery("fromUseruwhereusername=:name").setString("name",username).list();
if(result==null)
...{
throw.....
}
returnresult;
}
catch (HibernateExceptionex)
... {
throwconvetHibernateAccessException(ex);
}

编程式事务管理

自己组装业务实现的类 利用

org.springframework.transaction.support .TransactionTemplate

org.springframework.transaction.support.TransactionCallbackWithoutResult

org.springframework.orm.hibernate3.HibernateTemplate
org.springframework.transaction.TransactionStatus

org.springframework.orm.hibernate3.HibernateTransactionManager

org.springframework.transaction.TranscationDefinition

这些接口和方法来进行事务管理 看起来没有那么简洁

声明式事务管理

定义一个代理类

核心部分如下

<!-- =================================================================== -->
<!-- transactionManager -->
<!-- =================================================================== -->

< bean id ="transactionManager" class ="org.springframework.orm.hibernate3.HibernateTransactionManager" >
< property name ="sessionFactory" >
< ref bean ="sessionFactory" />
</ property >
</ bean >

<!-- =================================================================== -->
<!-- DaoProxy -->
<!-- =================================================================== -->

< bean id ="userDaoProxy" class ="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" >
< property name ="transactionManager" >
< ref bean ="transactionManager" />
</ property >
< property name ="proxyInterfaces" >
< list >
< value > com.ergal.hibernate.IUserDao </ value >
</ list >
</ property >
< property name ="target" >
< ref bean ="userDao" />
</ property >
< property name ="transactionAttributes" >
< props >
< prop key ="insert" > PROPAGATION_REQUIRED </ prop >
</ props >
</ property >

</ bean >