Hibernate 4 - 调用DAO并初始化sessionFactory bean [英] Hibernate 4 - Calling DAO and Initializing sessionFactory bean
问题描述
我正在将我的旧程序更新到Spring 3.2和Hibernate 4，并且遇到了一些与sessionFactory有关的困难（之前我正在使用hibernateTemplate）。
I'm in the middle of updating my old program to Spring 3.2 and Hibernate 4 and am running into a couple of difficulties with sessionFactory (I was using hibernateTemplate before).
-
我不认为我访问DAO的方式是最好的方法，但我不知道如何让它工作。如果我简单地创建DAO对象（CSSDAO d = new CSSDAOImpl（）;），则sessionFactory始终为null。如果我按照下面的方式使用它，它就可以了。调用DAO方法的正确方法是什么？ （请忽略控制器的MVC部分，我知道需要自己的工作）
I don't think the way I am accessing the DAO is the best way to do it, but I don't see how else to make it work. If I do a simple creation of the DAO object (CSSDAO d = new CSSDAOImpl();), the sessionFactory is always null. If I have it the way I do below, it works. What is the proper way to call the DAO methods? (please ignore the MVC portion of the controller, I know that needs its own work)
我在DAO的每个方法中打开一个新会话。我知道这不正确，因为我应该参加当前的会议。但每当我试图获得当前会话时，它就说不存在。会话如何第一次初始化？我认为它会基于XML配置注入它，但这似乎没有在这里做任何事情。有什么想法吗？
I'm opening a new session in every method in the DAO. I know this isn't correct, as I should be getting the current session. But everytime I try to get the current session, it says one doesn't exist. How does the session get "initialized" the first time? I thought it would inject it based on the XML configuration, but that doesn't seem to be doing anything here. Any thoughts?
hibernate-cfg.xml
<?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-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
<bean id="myDataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.apache.derby.jdbc.EmbeddedDriver"></property>
<property name="url" value="jdbc:derby:C:\Users\Steven\MyDB"></property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="packagesToScan" value="net.form" />
<property name="dataSource" ref="myDataSource"></property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.DerbyTenSevenDialect
</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
<property name="annotatedClasses">
<list>
<value>net.form.StyleChooser</value>
</list>
</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="CSSDAO" class="dao.CSSDAOImpl">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
</beans>
DAO：
package dao;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;
import net.form.StyleChooser;
public class CSSDAOImpl implements CSSDAO {
private SessionFactory sessionFactory;
@Autowired
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
@Transactional
public List selectAllCSS() {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
List l = session.createCriteria(StyleChooser.class).list();
session.flush();
tx.commit();
return l;
}
@Transactional
public StyleChooser selectCSSById(Integer ID) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
StyleChooser sc = (StyleChooser) session.get(StyleChooser.class, ID);
session.flush();
tx.commit();
return sc;
}
@Transactional
public Integer insertCSS(StyleChooser insertCSS) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Integer id = (Integer) session.save(insertCSS);
session.flush();
tx.commit();
return id;
}
@Transactional
public void deleteCSS(Integer CSSId) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
StyleChooser sc = (StyleChooser) session.get(StyleChooser.class, CSSId);
session.delete(sc);
session.flush();
tx.commit();
}
@Transactional
public void updateCSS(StyleChooser cssWithNewValues) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
session.update(cssWithNewValues);
session.flush();
tx.commit();
}
}
访问DAO ......
Accessing DAO...
package net.controllers;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import net.form.StyleChooser;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.multiaction.MultiActionController;
import dao.CSSDAOImpl;
@Controller
@RequestMapping("/stylechoosertable.html")
public class IndexController extends MultiActionController {
Resource resource = new FileSystemResource(
"C:/Users/Steven/Desktop/Programming/workspace/CSSGeneratorHibernate4/WebContent/WEB-INF/hibernate.cfg.xml");
BeanFactory beanFactory = new XmlBeanFactory(resource);
CSSDAOImpl dao = (CSSDAOImpl) beanFactory.getBean("CSSDAO");
@RequestMapping(method = RequestMethod.GET)
public ModelAndView showIndex(HttpServletRequest request) throws Exception {
List<StyleChooser> styleChooser = dao.selectAllCSS();
return new ModelAndView("stylechoosertable", "styleChooser", styleChooser);
}
}
推荐答案
少数观察：
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在检索方法中，不应使用交易，即它们应该是非交易的。
In your retrieve methods, transaction shouldn't be used i.e. they should be non-transactional.
在您的配置中添加< tx：annotation-driven transaction-manager =transactionManager/> 以识别事务注释。
Add <tx:annotation-driven transaction-manager="transactionManager"/> in your configuration to recognize the transactional annotations.
如果使用 @Transactional 注释，则不需要使用编程事务。将 @Transactional 注释中的propagation属性添加为 @Transactional（propagation = Propagation.REQUIRED）并保留事务管理休眠。
If you use @Transactional annotation then don't need to use programmatic transactions. Add the propagation attribute in the @Transactional annotation as @Transactional(propagation=Propagation.REQUIRED) and leave the transaction management to Hibernate.
第一次需要打开会话，如果没有关闭，下次可能会使用相同的会话。要获得会话，最好使用如下的实用工具方法：
For first time you need to open the session and if not closed you may use the same session next time. For getting the session, better to use an utility method as below:
private Session getSession(SessionFactory sessionFactory){
Session session = null;
try{
session = sessionFactory.getCurrentSession();
}catch(HibernateException hex){
hex.printStackTrace();
}
if(session == null && !session.isClosed()){
session = sessionFactory.openSession();
}
}
这样，您将获得会话（如果可用）并打开，否则打开新会话。
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