Jpa规范中persistence.xml 配置文件解析

使用spring data + hibernate 进行逻辑层操作时候需要配置 persistence.xml的内容

 
<?xml version="1.0"?>  

<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/persistence_1_0.xsd" version="1.0"> <persistence-unit name="itcast" transaction-type="RESOURCE_LOCAL"> <properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
<property name="hibernate.connection.driver_class" value="org.gjt.mm.mysqlDriver" />
<property name="hibernate.connection.username" value="root" />
<property name="hibernate.connection.password" value="root" />
<property name="hibernate.connection.url" value="jdbc.mysql://localhost:3306/testdatabase?useUnicode=true&characterEncoding=UTF-8" />
<property name="hibernate.max_fetch_depth" value="3" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
</properties> </persistence-unit>
 

下面是从网上搜索回来的配置文件每行说明:

 
<?xml version="1.0" encoding="UTF-8"?>  

<persistence version="1.0"
xmlns:persistence="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 persistence_1_0.xsd "> <!--
Name属性用于定义持久化单元的名字 (name必选,空值也合法);
transaction-type 指定事务类型(可选)
-->
<persistence-unit name="unitName" transaction-type="JTA"> <!-- 描述信息.(可选) -->
<description> </description> <!-- javax.persistence.PersistenceProvider接口的一个实现类(可选) -->
<provider> </provider> <!-- Jta-data-source和 non-jta-data-source用于分别指定持久化提供商使用的JTA和/或non-JTA数据源的全局JNDI名称(可选) -->
<jta-data-source>java:/MySqlDS</jta-data-source>
<non-jta-data-source> </non-jta-data-source> <!-- 声明orm.xml所在位置.(可选) -->
<mapping-file>product.xml</mapping-file> <!-- 以包含persistence.xml的jar文件为基准的相对路径,添加额外的jar文件.(可选) -->
<jar-file>../lib/model.jar</jar-file> <!-- 显式列出实体类,在Java SE 环境中应该显式列出.(可选) -->
<class>com.domain.User</class>
<class>com.domain.Product</class> <!-- 声明是否扫描jar文件中标注了@Enity类加入到上下文.若不扫描,则如下:(可选) -->
<exclude-unlisted-classes/> <!-- 厂商专有属性(可选) -->
<properties>
<!-- hibernate.hbm2ddl.auto= create-drop / create / update -->
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.show_sql" value="true" />
</properties> </persistence-unit> </persistence>
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