重建Hibernate的SessionFactory的方法(不重启服务)

本文介绍了一种在Hibernate中重新创建SessionFactory的方法,适用于动态修改数据库表结构的场景,如提供用户自定义表单功能。

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转载请注明出处:http://blog.youkuaiyun.com/sunyujia/

声明:本方法没有进行过除如下测试用例外的任何测试,不保证其稳定性,重建SessionFactory是非常危险的,本文只在于研究和学习。

没有深入研究过hibernate后台的机制,只是为了帮助论坛上的网友解决一个实际的问题,看了下Configuration类的源码,发现是protected的,写了个类继承它,改为public后,测试通过,本来没想到这么简单,不过暂时来看确实简单。不好意思发表,鉴于任何网络资源都会有益于人,还是发出来了。共广大程序员百度搜之。

本方法适合动态修改数据库表结构。例如提供给用户自定义表单功能。

  1. package com.syj.domain.test;
  2. import java.io.File;
  3. import org.hibernate.Session;
  4. import org.hibernate.SessionFactory;
  5. import org.hibernate.cfg.Configuration;
  6. import com.syj.domain.User;
  7. /**
  8.  * <p>
  9.  * Title: 重新创建SessionFactory的测试类
  10.  * </p>
  11.  *
  12.  * <p>
  13.  * Copyright: 转载请注明出处http://blog.youkuaiyun.com/sunyujia/
  14.  * </p>
  15.  *
  16.  * @author 孙钰佳
  17.  * @main sunyujia@yahoo.cn
  18.  * @date Oct 6, 2008 8:38:11 PM
  19.  */
  20. public class ResetHbmTest {
  21.     /**
  22.      * Description: 测试用例
  23.      *
  24.      * @param args
  25.      * @throws Exception
  26.      * @blog ht tp://blog.youkuaiyun.com/sunyujia/
  27.      * @mail sunyujia@yahoo.cn
  28.      * @since:Oct 6, 2008 8:38:11 PM
  29.      */
  30.     public static void main(String[] args) throws Exception {
  31.         HibernateConfiguration configuration = new HibernateConfiguration();
  32.         configuration.configure("/hibernate.cfg.xml");
  33.         SessionFactory sessionFactory = configuration.buildSessionFactory();
  34.         Session session = sessionFactory.openSession();
  35.         session.beginTransaction();
  36.         User u1 = new User();
  37.         session.save(u1);
  38.         session.getTransaction().commit();
  39.         session.refresh(u1);
  40.         System.out.println("user Id:" + u1.getId() + " name:" + u1.getName());
  41.         sessionFactory.close();
  42.         testReplaceXml();// 改变pojo xml文件
  43.         configuration.reset();// 重置
  44.         configuration.configure("/hibernate.cfg.xml");
  45.         sessionFactory = configuration.buildSessionFactory();// buildSessionFactory
  46.         session = sessionFactory.openSession();
  47.         session.beginTransaction();
  48.         User u2 = new User();
  49.         session.save(u2);
  50.         session.getTransaction().commit();
  51.         session.refresh(u2);
  52.         System.out.println("user Id:" + u2.getId() + " name:" + u2.getName());
  53.     }
  54.     /**
  55.      *
  56.      * Description:测试修改User.hbm.xml ,为了简单没考虑太多 简单替换
  57.      *
  58.      * @throws Exception
  59.      * @mail sunyujia@yahoo.cn
  60.      * @since:Oct 6, 2008 8:55:28 PM
  61.      */
  62.     public static void testReplaceXml() throws Exception {
  63.         File file = new File(User.class.getResource("User.hbm.xml").getFile());
  64.         String userHbmXml = org.apache.commons.io.FileUtils.readFileToString(
  65.                 file, "UTF-8");
  66.         userHbmXml = userHbmXml.replaceAll("(select 1)""(select 2)");
  67.         org.apache.commons.io.FileUtils.writeStringToFile(file, userHbmXml);
  68.     }
  69. }
  70. class HibernateConfiguration extends Configuration {
  71.     public HibernateConfiguration() {
  72.         super();
  73.     }
  74.     public void reset() {
  75.         super.reset();// 关键在这里,这个方法是protected的通过继承转换为public
  76.     }
  77. }
  1. <?xml version="1.0" encoding="utf-8"?>
  2. <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  3. "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  4. <hibernate-mapping>
  5.     <!-- ht tp://blog.youkuaiyun.com/sunyujia/ -->
  6.     <class name="com.syj.domain.User" table="Syj_User" schema="dbo" catalog="pubs">
  7.         <id name="id" type="java.lang.Integer">
  8.             <column name="id" />
  9.             <generator class="identity" />
  10.         </id>
  11.         <property name="name" type="java.lang.String">
  12.             <formula>(select 1)</formula>
  13.         </property>
  14.     </class>
  15. </hibernate-mapping>

测试结果如下

user Id:38 name:1

user Id:39 name:2

可以看出已经生效了。

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. 2025-07-20 08:51:19.595 ERROR 9284 --- [ restartedMain] o.s.boot.SpringApplication : Application run failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1694) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:573) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1087) ~[spring-context-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:857) ~[spring-context-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:548) ~[spring-context-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) [spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:386) [spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1242) [spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1230) [spring-boot-2.0.7.RELEASE.jar:2.0.7.RELEASE] at com.gms.user.UserApplication.main(UserApplication.java:11) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_452] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_452] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_452] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_452] at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.7.RELEASE.jar:2.0.7.RELEASE] Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:861) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:888) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1753) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1690) ~[spring-beans-5.0.11.RELEASE.jar:5.0.11.RELEASE] ... 21 common frames omitted Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:100) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:54) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:137) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final] ... 38 common frames omitted 这是什么错误
最新发布
07-21
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