我正在使用以下架构在 Spring 应用程序中开发 Hibernate DAO:
我有一个 PersonDAO 接口,我在其中声明了我想要的 CRUD 方法,然后我创建了一个具体的类 PersonDAOImpl 来实现这个接口,这个:
package org.andrea.myexample.HibernateOnSpring.dao;
import org.andrea.myexample.HibernateOnSpring.entity.Person;
import org.hibernate.SessionFactory;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
@Transactional
public class PersonDAOImpl2 {
// Factory per la creazione delle sessioni di Hibernate:
private static SessionFactory sessionFactory;
// Metodo Setter per l'iniezione della dipendenza della SessionFactory:
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
System.out.println("Ho iniettato la SessionFactory: " + sessionFactory);
}
/** CREATE CRUD Operation:
* Aggiunge un nuovo record rappresentato nella tabella rappresentato
* da un oggetto Person
*/
@Transactional(readOnly = false)
public Integer addPerson(Person p) {
System.out.println("Inside addPerson()");
System.out.println("Connessione aperta: " + sessionFactory.getCurrentSession().isOpen());
System.out.println("E' connesa:" + sessionFactory.getCurrentSession().isConnected());
Integer personID = personID = (Integer) sessionFactory.getCurrentSession().save(p);
return personID;
}
}
然后我创建了一个包含 main() 方法的MainApp类来测试它是如何工作的。
问题是当我尝试在数据库中插入新记录时执行 MainApp 时,我在堆栈跟踪中获得以下错误消息:
INFO: Using DataSource [org.apache.commons.dbcp.BasicDataSource@446adaa2] of Hibernate SessionFactory for HibernateTransactionManager
Ho iniettato la SessionFactory: org.hibernate.internal.SessionFactoryImpl@34a8a14b
Contesto recuperato: org.springframework.context.support.ClassPathXmlApplicationContext@70501e4e: startup date [Sat Mar 09 10:02:37 CET 2013]; root of context hierarchy
Creato persona1: org.andrea.myexample.HibernateOnSpring.entity.Person@2d35bcd7
Exception in thread "main" java.lang.ClassCastException: org.andrea.myexample.HibernateOnSpring.dao.PersonDAOImpl2$$EnhancerByCGLIB$$d0c4a932 cannot be cast to org.andrea.myexample.HibernateOnSpring.dao.PersonDAO
at org.andrea.myexample.HibernateOnSpring.MainApp.main(MainApp.java:26)
似乎它没有找到 Session 对象,现在我有一个疑问:我知道 Spring 会为每个 @Transactional 方法自动打开和关闭 Session 但它似乎不起作用!
相反,如果我在调用该方法时显式打开一个新会话,它会很好地工作......以这种方式:
@Transactional(readOnly = false)
public Integer addPerson(Person p) {
System.out.println("Inside addPerson()");
Session session = sessionFactory.openSession();
Transaction tx = null;
Integer personID = null;
try {
tx = session.beginTransaction();
personID = (Integer) session.save(p);
tx.commit();
} catch (HibernateException e) {
if (tx != null)
tx.rollback();
e.printStackTrace();
} finally {
session.close();
}
return personID;
}
但我认为我可以说 Spring 在进入方法时自动打开 Session 并在退出时关闭它
这是我的 XML 配置文件:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd ">
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/SpringTestDb" />
<property name="username" value="root" />
<property name="password" value="MY_DB_PSWD" />
<property name="initialSize" value="2" />
<property name="maxActive" value="5" />
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="org.andrea.myexample.HibernateOnSpring.entity" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
<prop key="hibernate.show_sql">false</prop>
</props>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="personDAOImpl" class="org.andrea.myexample.HibernateOnSpring.dao.PersonDAOImpl2" >
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<!-- Register @Autowired annotation -->
<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />
</beans>
有人可以帮助我吗?
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