hello hibernate

最新推荐文章于 2020-10-12 18:02:01 发布

原创最新推荐文章于 2020-10-12 18:02:01 发布 · 984 阅读

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这几天闲着无事就看了看hibernate

看的视频是北京尚学堂马士兵的版本是3.2 我自己下的是4.3.5 中间出了一堆问题现记录下来

项目组织图如下

首先就是要

遇到的几个问题

问题一:

如果我们通过sessionfactory.getCurrentSession来获得session,那么在配置文件里,我们就得加上

<property name="current_session_context_class">thread</property>

如果单纯的使用sessionfactory来获得session,那么上面的代码,加与不加都OK

问题二:

package com.bjsxt.hibernate;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

import util.HibernateUtil;

public class StuTest {
    public static void main(String[] args) {
        Stu s = new Stu();
        s.setId(48236);
        s.setName("zhangsan"); 
        s.setAge(8);
        
    //    SessionFactory sessionFactory = 
    //            new AnnotationConfiguration().configure().buildSessionFactory();
    //    Session session = sessionFactory.getCurrentSession();
        Session session= HibernateUtil.getSessionFactory().getCurrentSession();
    
        session.beginTransaction();
        session.save(s);
        session.getTransaction().commit();
    }

}

首先就是在4.3中buildSessionFactory被废除了

相应的部分应该改成这样

		Configuration cfg = new Configuration().configure();
		StandardServiceRegistryBuilder srb =
				new StandardServiceRegistryBuilder()
				.applySettings(cfg.getProperties());
		StandardServiceRegistry sr = srb.build();
		SessionFactory sf = cfg.buildSessionFactory(sr);

见参考资料1

其实更方便的就是设置util类如下

package util;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;

public class HibernateUtil4 {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
        	Configuration cfg = new Configuration().configure();
    		StandardServiceRegistryBuilder srb =
    				new StandardServiceRegistryBuilder()
    				.applySettings(cfg.getProperties());
    		StandardServiceRegistry sr = srb.build();
    		return cfg.buildSessionFactory(sr);
        }
        catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
		
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

}

参考4.3的说明文档我就想不通了

 try {
            // Create the SessionFactory from hibernate.cfg.xml
            new Configuration().configure().buildSessionFactory(
			    new StandardServiceRegistryBuilder().build() );
        }

为什么不return? 难道我想错了?

问题二:

<property name="hbm2ddl.auto">creat</property>

加上这句话就能让hibernate自动建表

可我的console上就是没有droptable creat teble

最后想是不是日志文件有问题倒腾了半天

哎

hbm2ddl.auto 里面是create 不是creat!!!

另外,如果hibernate的配置信息在spring中,那么像之前的hbm2ddl.auto前面都得加上hibernate

例如

<pre name="code" class="html"><bean id="sessionFactory"
		class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
		<property name="dataSource">
			<ref bean="dataSource" />
		</property>
		<property name="packagesToScan">
			<list>
				<value>cdm.core.model</value>
			</list>
		</property>
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">
					org.hibernate.dialect.Oracle9Dialect
				</prop>
			
			<prop key="hibernate.hbm2ddl.auto">update</prop>
				<prop key="hibernate.show_sql">true</prop>
				<prop key="hibernate.format_sql">true</prop>


				<prop key="current_session_context_class">thread</prop>
			</props>
		</property>
	</bean>