【Hibernate】初遇Hibernate

本文介绍了Hibernate作为ORM框架的角色及其如何简化Java应用与关系型数据库之间的交互。探讨了Hibernate的优点,如提高开发效率、增强代码的面向对象特性及良好的移植性,并讨论了其局限性。

        传统的三层架构,自上而下的单向依赖。层与层之间依赖于抽象。Hibernate其实说白了就是对jdbc再次进行了封装。Hibernate的核心工作就是完成OR映射。



        Hibernate是程序和数据库之间的桥梁。为什么有这个?jdbc的开发有很多的冗余,Java是面向对象的语言,但是我们的数据库大多是关系型数据库。Hibernate实现ORM思想一门技术。实现对象到关系型数据的映射。于是实现了程序的开发更加的面向对象。Hibernate实现了数据的封装,移植性很强,其次Hibernate是轻量级的(没有侵入性),基于这些特性,Hibernate很流行。

        Hibernate的缺点:

  1.    使用数据库特性的语句,很难调优。
  2.    对大批量数据更新存在问题。
  3.    系统中存在大量的统计查询功能,Hibernate不大适用。

        小结:通过学习Hibernate了解他持久化的思想是最重要的,目前为止还没有动手上例子,期待吧,后续的博客中会有的。

         题外话:2017年悄无声息的就来临了,我还没韵过味,2016就头也不回的离开了。受逛贴吧的影响,我也在想2016年自己哪些地方做的不足。问了问身边的朋友,发现他们的评论几乎神同步,都评论我特容易情绪化的对人。我若是喜欢你,那看你便是哪都是好的,若是不喜欢你,那看你就哪哪都是招我烦的。可能是我残留着文科生的一些神经质吧,总觉得有些人,只要看一眼就觉得彼此的磁场是相互吸引的,而有的人就是看一眼就知道不是同道中人。大概就是因为这种骨子里就带来的潜意识,让我自动完成了过滤,同时也做不到左右逢源,在2017年里还是该改掉这个,学着用放大镜看人家身上的优点,哪怕是不同磁场的人,指不定他们身上有更多我陌生但却急需学习的地方。此外就是在计算机的学习上面,近期发现一个很神奇的点就是之前看不懂的书,现在看起来居然会觉得很带劲,请允许我偷偷的乐两下下。


org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration cn.hutool.extra.spring.SpringUtil org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration com.github.yulichang.interceptor.MPJInterceptor 2025-08-20 23:31:29.758 ERROR --- [ restartedMain] o.springframework.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 javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.SQLGrammarException: Unable to open JDBC Connection for DDL execution at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:438) at org.springframework.boot.SpringApplication.run(SpringApplication.java:337) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1336) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1325) at com.jingji.st.JingjiTimingApplication.main(JingjiTimingApplication.java:18) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.SQLGrammarException: Unable to open JDBC Connection for DDL execution at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:421) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782) ... 21 common frames omitted Caused by: org.hibernate.exception.SQLGrammarException: Unable to open JDBC Connection for DDL execution at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:63) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:99) at org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl.getIsolatedConnection(DdlTransactionIsolatorNonJtaImpl.java:69) at org.hibernate.tool.schema.internal.exec.ImprovedExtractionContextImpl.getJdbcConnection(ImprovedExtractionContextImpl.java:60) at org.hibernate.tool.schema.internal.exec.ImprovedExtractionContextImpl.getJdbcDatabaseMetaData(ImprovedExtractionContextImpl.java:67) at org.hibernate.tool.schema.extract.internal.InformationExtractorJdbcDatabaseMetaDataImpl.getTables(InformationExtractorJdbcDatabaseMetaDataImpl.java:333) at org.hibernate.tool.schema.extract.internal.DatabaseInformationImpl.getTablesInformation(DatabaseInformationImpl.java:120) at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:65) at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207) at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114) at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184) at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73) at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:318) at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:468) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1259) at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ... 25 common frames omitted Caused by: java.sql.SQLSyntaxErrorException: Unknown database 'jijing-dev' at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:833) at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:453) at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198) at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180) at org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl.getIsolatedConnection(DdlTransactionIsolatorNonJtaImpl.java:43) ... 40 common frames omitted
08-21
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