Question

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）。

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）
我正在DAO中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。会话如何在第一次“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？

冬眠-cfg.xml中

    <?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 ......

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);
    }
}

Answer 1

很少观察：

在您的检索方法中，不应使用交易，即它们应该是非交易的。
在配置中添加<tx:annotation-driven transaction-manager="transactionManager"/>以识别交易注释。
如果您使用@Transactional注释，则无需使用编程式事务。将@Transactional注释中的propagation属性添加为@Transactional(propagation=Propagation.REQUIRED)，并将事务管理保留为Hibernate。

您第一次需要打开会话，如果没有关闭，您可能会在下次使用相同的会话。要获得session，最好使用如下的实用程序方法：

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。

Hibernate 4 - 调用DAO并初始化sessionFactory bean

1 个答案: