Spring配置事务的三种方式

步骤：数据源配置-事务配置(xml配置方式或注解方式)

如果要使用注解方式依赖注入sessionFactory到业务Bean中(使用@Resource)或者注入entityManager到业务Bean中(使用@PersistenceContext ),要加入<context:annotation-config/>

1.使用数据源：

<!-- 配置数据源 -->
<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close"
>
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url"
value="jdbc:mysql://localhost:3306/hib?useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
<property name="initialSize" value="1"/>
<property name="maxActive" value="100"/>
<property name="maxIdle" value="2"/>
<property name="minIdle" value="1"/>
</bean>

<!-- 数据源事务管理器-->
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager" >
<property name="dataSource" ref="dataSource"/>
</bean>

<!-- 注解方式配置事务 -->
<tx:annotation-driven transaction-manager="txManager"/>

2.使用Hibernate。

（1）.配置数据源同上。

（2）.配置sessionFactory

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="mappingResources">
<list>
<value>com/tazi/domin/Person.hbm.xml</value>
</list>
</property>
<property name="hibernateProperties">
<value>
hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.show_sql=true
hibernate.format_sql=true
hibernate.hbm2ddl.auto=update
</value>
</property>
</bean>

(3).配置事务管理器

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

（4）.注解方式配置事务同上。

3.使用JPA

(1).配置持久化数据单元

src/META-INF/persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">

<persistence-unit name="jpaPU" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name = "hibernate.connection.driver_class" value = "com.mysql.jdbc.Driver"/>
<property name = "hibernate.connection.url" value = "jdbc:mysql://localhost:3306/hib"/>
<property name = "hibernate.connection.username" value = "root"/>
<property name = "hibernate.connection.password" value = "123456"/>
<property name = "hibernate.hbm2ddl.auto" value = "update"/>
</properties>
</persistence-unit>

</persistence>

(2).配置entityManagerFactory

<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
<property name="persistenceUnitName" value="jpaPU" />
</bean>

(3).配置事务管理器

<bean id="transactionManager"
class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

(4).注解方式配置事务同上。

分析spring源代码

LocalEntityManagerFactoryBean中的方法createNativeEntityManagerFactory()。由以下代码可以看出Spring可以利用JPA的实现产品(这里是Hibernate)来创建实体管理器工厂(EntityManagerFactory)。

protected EntityManagerFactory createNativeEntityManagerFactory()
throws PersistenceException
{
//日志记录省略

PersistenceProvider provider = getPersistenceProvider();
if (provider != null)
{
EntityManagerFactory emf = provider.createEntityManagerFactory(getPersistenceUnitName(), getJpaPropertyMap());
if (emf == null) {
throw new IllegalStateException("PersistenceProvider [" + provider + "] did not return an EntityManagerFactory for name '" + getPersistenceUnitName() + "'");
}

return emf;
}

return Persistence.createEntityManagerFactory(getPersistenceUnitName(), getJpaPropertyMap());
}

LocalEntityManagerFactoryBean并没有实现EntityManagerFactory接口，配置它得到EntityManagerFactory对象的原因是它实现了spring框架中的FactoryBean接口，从而Spring可以通过调用接口方法getObject等创建EntityManagerFactory实现者的实例。