下面是我從網上找到的關於JPA配置檔案persistence.xml的相關描述：

 1 <?xml version="1.0" encoding="UTF-8"?>  
 2   
 3 <persistence version="1.0"  
 4 xmlns:persistence="http://java.sun.com/xml/ns/persistence"  
 5 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
 6 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_1_0.xsd "
 
>  
 7   
 8 <!--    
 9      Name屬性用於定義持久化單元的名字 (name必選,空值也合法);   
10      transaction-type 指定事務型別(可選)    
11 -->  
12 <persistence-unit name="LMS" transaction-type="JTA">  
13   
14    <!-- 描述資訊.(可選) -->  
15    <description> </description>  
16   
17    <!--
 
 javax.persistence.PersistenceProvider介面的一個實現類(可選) -->  
18    <provider>   </provider>  
19   
20    <!-- Jta-data-source和 non-jta-data-source用於分別指定持久化提供商使用的JTA和/或non-JTA資料來源的全域性JNDI名稱(可選) -->  
21    <jta-data-source>java:/LMSNGDataSource_UW</jta-data-source>  
22    <
 
non-jta-data-source> </non-jta-data-source>  
23   
24    <!-- 宣告orm.xml所在位置.(可選) -->  
25    <mapping-file>product.xml</mapping-file>  
26   
27    <!-- 以包含persistence.xml的jar檔案為基準的相對路徑,新增額外的jar檔案.(可選) -->  
28    <jar-file>../lib/model.jar</jar-file>  
29   
30    <!-- 顯式列出實體類,在Java SE 環境中應該顯式列出.(可選) -->  
31    <class>com.domain.User</class>  
32    <class>com.domain.Product</class>  
33   
34    <!-- 宣告是否掃描jar檔案中標註了@Enity類加入到上下文.若不掃描,則如下:(可選) -->  
35    <exclude-unlisted-classes>true</exclude-unlisted-classes>
36   <!--可選 -->
37   <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
38    <!--   廠商專有屬性(可選)   -->  
39    <properties>  
40     <!-- hibernate.hbm2ddl.auto= create-drop / create / update -->  
41     <property name="hibernate.cache.use_second_level_cache"
42                 value="true" />
43     <property name="hibernate.cache.use_query_cache" value="true" />
44     <property name="hibernate.hbm2ddl.auto" value="update" />  
45     <property name="hibernate.show_sql" value="true" />  
46    </properties>  
47   
48 </persistence-unit>  
49   
50 </persistence>