我知道这个问题已经讨论过很多次了。我只是不明白这是如何工作的或者我的错误在哪里。
我认为给你一个简化的例子是向你展示我正在尝试做的事情以及我正在采取的假设的最佳方式......
我有一个带有名称的产品类。该名称是一个惰性的 String 属性。
My DAO:
public abstract class HibernateProductDAO extends HibernateDaoSupport implements ProductDAO
{
public List getAll()
{
return this.getHibernateTemplate().find("from " + this.getDomainClass().getSimpleName());
}
}
我的服务接口：
public interface ProductService {
//This methods are Transactional, but same exception error is thrown if there weren't
@Transactional
public Product getProduct();
@Transactional
public String getName(Product tp);
}
我的服务实施：
public class ProductServiceImpl implements ProductService {
private ProductDAO productDAO;
public Product getProduct() {
List ps = this.productDAO.getAll();
return (Product) ps.get(0);
}
public String getName(Product p){
return p.getName();
}
}
我的主要课程：
public class Main {
private ProductService productService;
public static void main(String[] args) {
Main main= new Main();
main.productService= (ProductService)(new ClassPathXmlApplicationContext("applicationContext.xml")).getBean("productProxy");
//load the product without the name
Product p = main.productService.getProduct();
//load the lazy name
System.out.println(main.productService.getName(p)); //EXCEPTION IS THROWN IN THIS LINE
}
public void setProductService(ProductService productService) {
this.productService= productService;
}
public ProductService getProductService() {
return productService;
}
我的applicationContext.xml：
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:lang="http://www.springframework.org/schema/lang"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:sca="http://xmlns.oracle.com/weblogic/weblogic-sca">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName"><value>oracle.jdbc.driver.OracleDriver</value></property>
<property name="url"><value>jdbc:oracle:thin:@${hostname}:${port}:${schema}</value></property>
<property name="username"><value>${username}</value></property>
<property name="password"><value>${password}</value></property>
</bean>
<!-- Hibernate SessionFactory -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource"><ref local="dataSource"/></property>
<property name="configLocation"><value>hibernate.cfg.xml</value></property>
<property name="configurationClass"><value>org.hibernate.cfg.AnnotationConfiguration</value></property>
</bean>
<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory"><ref local="sessionFactory"/></property>
</bean>
<bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
<property name="sessionFactory"><ref bean="sessionFactory"/></property>
<property name="allowCreate" value="true"/>
</bean>
<bean id="productDAO" class="product.model.data.ProductDAO" >
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="hibernateInterceptor"
class="org.springframework.orm.hibernate3.HibernateInterceptor">
<property name="sessionFactory">
<ref bean="sessionFactory"/>
</property>
</bean>
<bean id="productService"
class="product.services.ProductServiceImpl">
<property name="productDAO">
<ref bean="ProductDAO"/>
</property>
</bean>
<bean id="productProxy"
class="org.springframework.aop.framework.ProxyFactoryBean">
<property name="target">
<ref bean="productService"/>
</property>
<property name="proxyInterfaces">
<value>product.services.ProductService</value>
</property>
<property name="interceptorNames">
<list>
<value>hibernateInterceptor</value>
</list>
</property>
</bean>
</beans>
异常片段：
11:59:57,775 [main] DEBUG org.springframework.orm.hibernate3.SessionFactoryUtils - Opening Hibernate Session
11:59:57,775 [main] DEBUG org.hibernate.impl.SessionImpl - opened session at timestamp: 12749723977
11:59:57,777 [main] ERROR org.hibernate.LazyInitializationException - could not initialize proxy - no Session
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:108)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:150)
at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150)
如果我假设 HibernateInterceptor 在不同的调用中保持 Hibernate 会话打开，我是对的吗？如果是这样，为什么会话在加载产品对象后关闭？
我在某处读到我也可以使用 OpenSessionInViewInterceptor，但我无法使其工作。您将如何将该拦截器添加到这个小示例中？
是否存在任何代码错误或对其工作原理的误解？
你知道我可以下载什么简单的示例代码来检查它是如何工作的吗？
提前致谢，
内乌基诺
