2
我知道這已經被討論了很多次。我不明白這項工作或我的錯誤在哪裏。
我認爲給你一個簡化的例子是告訴你我想要做什麼以及我正在採取什麼假設的最好方法...Spring/Hibernate需要的幫助懶惰加載
我有一個帶名稱的產品類。該名稱是一個懶惰的String屬性。
吾道：
public abstract class HibernateProductDAO extends HibernateDaoSupport implements ProductDAO
{
public List getAll()
{
return this.getHibernateTemplate().find("from " + this.getDomainClass().getSimpleName());
}
}
我的服務接口：
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);
}
我的服務實現：
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();
}
}
我的主類：
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>
異常片段：
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)
我說得對，如果我假設器HibernateInterceptor保持不同的呼叫中Hibernate的Session打開？如果我是這樣的話，爲什麼會在加載產品對象後關閉會話？
我在某處讀了我也可以使用OpenSessionInViewInterceptor，但我無法使它工作。你如何將這個攔截器添加到這個小例子中？
有沒有任何代碼錯誤或錯誤理解如何工作？
你知道任何簡單的示例代碼，我可以下載來檢查它是如何工作的嗎？
由於提前， Neuquino