JPA配置文档persistence.xml文件的参数说明

JPA配置文档persistence.xml文件的参数说明JPA规范要求在类路径的META-INF目录下放置persistence.xml,文件的名称是固定的，配置模板如下：Xml代码

JPA规范要求在类路径的META-INF目录下放置persistence.xml, 文件的名称是固定的，配置模板如下：   
  
Xml代码  
<?xml version="1.0" encoding="UTF-8"?>  
<persistence version="2.1"  
 xmlns="<a target=_blank href="http://xmlns.jcp.org/xml/ns/persistence">http://xmlns.jcp.org/xml/ns/persistence</a>" xmlns:xsi="<a target=_blank href="http://www.w3.org/2001/XMLSchema-instance">http://www.w3.org/2001/XMLSchema-instance</a>"  
 xsi:schemaLocation="<a target=_blank href="http://xmlns.jcp.org/xml/ns/persistence">http://xmlns.jcp.org/xml/ns/persistence</a>  
 <a target=_blank href="http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd</a>">  
    
<persistence-unit name="persist-unit"  
  transaction-type="RESOURCE_LOCAL">  
  <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>  
  <!-- All persistence classes must be listed -->  
  <class>boa.framework.entity.CustomerEntity</class>                                                                                 <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>  
   <validation-mode>CALLBACK</validation-mode>       
  <properties>  
   <!-- Provider-specific connection properties -->  
   <property name="javax.persistence.jdbc.url" value="jdbc:derby:memory:exampleDB;create=true" />  
   <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.EmbeddedDriver" />  
   <property name="javax.persistence.jdbc.user" value="" />  
   <property name="javax.persistence.jdbc.password" value="" />  
   <property name="javax.persistence.schema-generation.database.action"  
    value="drop-and-create" />  
   <property name="javax.persistence.schema-generation.create-source"  
    value="script" />  
   <property name="javax.persistence.schema-generation.create-script-source"  
    value="META-INF/create-script.sql" />  
   <property name="eclipseink.logging.level" value="INFO" />  
  </properties>  
 </persistence-unit>  
</persistence>    
  
  
    
<!--     
      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:/test</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>boa.framework.entity.CustomerEntity</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>true</exclude-unlisted-classes>　  
　　　shared-cache-mode  
　　缓存模式。加了@Cacheable注解的默认为二级缓存。有四种模式：ALL-缓存所有实体；NONE-禁止缓存；ENABLE_SELECTIVE-如果加了缓存的标识，是默认的选选　　　　　　　　项；DISABLE_SELECTIVE- enable caching unless explicitly marked as  @Cacheable(false) (not  recommended)  
　　validation-mode  
　　实体的验证模式，默认是激活的。当一个实体在创建、更新，在实体发送到数据库前会被进行验证。CALLBACK: entities are validated on creation, update and deletion. If no Bean Validation provider  is present, an exception is raised at initialization time.                        <!--    厂商专有属性(可选)    -->    
   <properties>    
    <!-- hibernate.hbm2ddl.auto= create-drop / create / update -->    
      <property name="eclipseink.logging.level" value="INFO" />    
   </properties>    
    
</persistence-unit>    
    
</persistence>