Spring2.5 + JPA(Hibernate)实现

1.JPA的实现框架

     使用MyEclipse7.1可以加入TopLink、Hibarnate、OpenJPA和EclipseLink。这几种框架，我已经简单测试使用过。基本上没什么区别（当然是对于JPA来说的）。

     使用Hibernate JPA、EclipseLink、OpenJPA 时，Entity Bean的主键生成celve可以采取@GeneratedValue(strategy = GenerationType.AUTO)，可以的MySQL和Oracle之间灵活转换。注：日期类型把注解@Temporal(TemporalType.TIMESTAMP)去掉可以正常执行。

     使用TopLink 的时候，MySQL的主键生产策略只能采取@GeneratedValue(strategy = GenerationType.IDENTITY)，这样一来，就和MySQL数据库耦合了，以后更换数据库还得该代码了。如果采取的是Oracle的话，理论上建议使用TopLink。TopLink是Oracle公司的框架，对于Oracle性能上可能会好一点。至于是否真的好一点，很难说，没有测试数据。我也只能“人云亦云”了。

     使用OpenJPA 的时候，对于MyEclipse反向生成Entity，居然不需要修改（指日期类型），对于@Temporal一般不会用到，直接删除就行了。

 

2.persistence.xml

    

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
    
	<persistence-unit name="Spring_JPAPU"
		transaction-type="RESOURCE_LOCAL">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		<class>com.taoistwar.jpa.entity.User</class>
		<properties>
			<property name="hibernate.connection.driver_class"
				value="com.mysql.jdbc.Driver" />
			<property name="hibernate.connection.url"
				value="jdbc:mysql://127.0.0.1:3306/jpa" />
			<property name="hibernate.connection.username" value="root" />
			<property name="hibernate.connection.password" value="root" />
		</properties>
	</persistence-unit>

</persistence>

 

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
    
	<persistence-unit name="Spring_JPA_TopLinkPU" transaction-type="RESOURCE_LOCAL">
		<provider>oracle.toplink.essentials.PersistenceProvider</provider>
  		<class>com.taoistwar.jpa.entity.User</class>
  		<properties>
			<property name = "toplink.jdbc.driver" value = "com.mysql.jdbc.Driver"/>
			<property name = "toplink.jdbc.url" value = "jdbc:mysql://127.0.0.1:3306/jpa"/>
			<property name = "toplink.jdbc.user" value = "root"/>
			<property name = "toplink.jdbc.password" value = "root"/>
	  	</properties>
	</persistence-unit>
  
</persistence>

 

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
    
	<persistence-unit name="Spring_JPA_OpenJPAPU"
		transaction-type="RESOURCE_LOCAL">
		<provider>
			org.apache.openjpa.persistence.PersistenceProviderImpl
		</provider>
		<class>com.taoistwar.jpa.entity.User</class>
		<properties>
			<property name="openjpa.ConnectionDriverName"
				value="com.mysql.jdbc.Driver" />
			<property name="openjpa.ConnectionURL"
				value="jdbc:mysql://127.0.0.1:3306/jpa" />
			<property name="openjpa.ConnectionUserName" value="root" />
			<property name="openjpa.ConnectionPassword" value="root" />
		</properties>
	</persistence-unit>

</persistence>

 

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
    
	<persistence-unit name="Spring_JPA_EclipseLinkPU"
		transaction-type="RESOURCE_LOCAL">
		<provider>
			org.eclipse.persistence.jpa.PersistenceProvider
		</provider>
		<class>com.taoistwar.jpa.entity.User</class>
		<properties>
			<property name="eclipselink.jdbc.driver"
				value="com.mysql.jdbc.Driver" />
			<property name="eclipselink.jdbc.url"
				value="jdbc:mysql://127.0.0.1:3306/jpa" />
			<property name="eclipselink.jdbc.user" value="root" />
			<property name="eclipselink.jdbc.password" value="root" />
		</properties>
	</persistence-unit>

</persistence>

 

 

 

 

 

备注：附件是的MyEclipse7.1中开发的。