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&amp;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。