1. Native Hibernate APIs and hbm.xml Mappings
2. Native Hibernate APIs and Annotation Mappings
3. Java Persistence API (JPA)
第一种方式对象类的定义和对象与数据库间的映射配置信息是分开的,对象类就是一平常Java类,配置信息就一hbm.xml文件。用这种方式,看似划分清晰,但写起来和用起来感觉不是太爽,一是写的东西多,写的多出错的机会就大;二是不停地在对象类和配置文件间来回切换,闪得慌。第二种方式直接将hbm.xml配置文件扔掉,将配置信息以Annotation风格与对象类紧密结合在一起。整合之后感觉清爽不少,少写了不少代码,对象属性与数据库表紧密结合,代码维护成本大大减少。第三种方式采用了JPA 2.0,JPA是ORM的一种规范,定义了操作的标准接口,对应该接口已有几种实现:Hibernate,EclipseLink。与第二种方式相比,JPA方式需要一persistence.xml配置文件。
对比上述三种方式,个人比较倾向于第三种,原因一是拥有Annotation带来的优点,二来如果那天不想使用Hibernate了,改用其他类似EclipseLink,或者其他的ORM,更换代价非常小。
Spring 3.1相比之前版本,出现了一新特征:JPA EntityManageFactory bootstrapping without persistence.xml。这一特征的出现,进一步简化了Spring与JPA间的整合:移走persistence.xml。
下面就是对Spring与JPA 2.0 (Hibernate 4)整合的配置文件:
- <?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:p="http://www.springframework.org/schema/p"
- xmlns:tx="http://www.springframework.org/schema/tx"
- xmlns:context="http://www.springframework.org/schema/context"
- xmlns:util="http://www.springframework.org/schema/util"
- xsi:schemaLocation="
- http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
- http://www.springframework.org/schema/tx
- http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
- http://www.springframework.org/schema/context
- http://www.springframework.org/schema/context/spring-context-3.1.xsd
- http://www.springframework.org/schema/util
- http://www.springframework.org/schema/util/spring-util-3.1.xsd">
- <!-- Data Source -->
- <bean id="dataSource"
- class="org.springframework.jdbc.datasource.DriverManagerDataSource">
- <property name="driverClassName" value="com.mysql.jdbc.Driver" />
- <property name="url" value="jdbc:mysql://localhost:3306/hibernate" />
- <property name="username" value="root" />
- <property name="password" value="" />
- </bean>
- <!-- This will ensure that Hibernate or JPA exceptions are automatically
- translated into Spring's generic DataAccessException hierarchy for those
- classes annotated with Repository. For example, see ***DAOImpl. -->
- <bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" />
- <!-- JPA Entity Manager Factory -->
- <bean id="entityManagerFactory"
- class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
- p:packagesToScan="com.haibin.rest" p:dataSource-ref="dataSource"
- p:jpaVendorAdapter-ref="hibernateVendor" p:jpaPropertyMap-ref="jpaPropertyMap" />
- <util:map id="jpaPropertyMap">
- <entry key="hibernate.hbm2ddl.auto" value="update" />
- <entry key="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
- <!-- To enable Hibernate's second level cache and query cache settings -->
- <entry key="hibernate.max_fetch_depth" value="4" />
- <entry key="hibernate.cache.use_second_level_cache" value="true" />
- <entry key="hibernate.cache.use_query_cache" value="true" />
- <entry key="hibernate.cache.region.factory_class" value="org.hibernate.cache.ehcache.EhCacheRegionFactory" />
- </util:map>
- <bean id="hibernateVendor"
- class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
- p:database="MYSQL" p:showSql="true" p:generateDdl="true"
- p:databasePlatform="org.hibernate.dialect.MySQLDialect" />
- <!-- Transaction Config -->
- <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"
- p:entityManagerFactory-ref="entityManagerFactory">
- <property name="jpaDialect">
- <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
- </property>
- </bean>
- <!-- User declarative transaction management -->
- <tx:annotation-driven transaction-manager="transactionManager" />
- </beans>
配置文件主要包含了5个部分:
1. Data source Configuration
2. JPA Entity Manager Factory Configuration
3. Transaction Configuration
4. Transaction Management
5. Exception
具体内容就不赘述了,尝试一下的话,可以参考或修改:Spring+JPA
注:最近写了一篇综合运用Spring各种相关技术的博文,涉及到技术包含了Spring 3.1.3, Spring MVC, Hibernate 4.1.7, EhCache, Spring Data JPA 1.1.0, MySQL 5, Spring Security 3.1.3, Spring Mail, Recapcha, c3p0,博文包含了各种技术的详尽配置信息,最后给出了可运行的源码。新博文对数据相关的配置进行了更新请查阅:基于Spring的注册登录系统,配置请查看第6部分spring-data.xml配置文件。