在J2SE环境中使用JPA

1.配置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="BookStorePU" transaction-type="RESOURCE_LOCAL">
  		<provider>org.hibernate.ejb.HibernatePersistence</provider>
  		<properties>
              <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
              <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/jpademo"/>
              <property name="hiberante.cnnection.username" value="root"/>
  		<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
  		<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
  		<property name="hibernate.show_sql" value="true"/>
  		<property name="hibernate.format_sql" value="true"/>
  		</properties>
	</persistence-unit>
  
</persistence>

2.在J2SE环境中只能使用应用托管的EntityManager并且手工控制事务。

public class TestClient{
  public static void main(String[] args){
   EntityManagerFactory emf=Persistence.createEntityManagerFactory("BookStorePU");
  EntityManager em=emf.createEntityManager();
  try{
   //事务的开始
   em.getTransaction().begin();
   /*实体操作*/
  //事务的提交
  em.getTransaction().commit()
  }finally{
     em.close();
     emf.close();
  }
}

}

3.将JPA实现者的jar包添加到运行类路径中。

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在web环境下使用JPA

1.持久化事务类型为RESOURCE_LOCAL

2.配置数据源建议采用JNDI方式，通过<non-jta-data-source>

<?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="BookStorePU" transaction-type="RESOURCE_LOCAL">
  		<provider>org.hibernate.ejb.HibernatePersistence</provider>
             <non-jta-data-source>java:comp/env/jdbc/jpademo</non-jta-data-source>
  		<properties>

  		<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
  		<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
  		<property name="hibernate.show_sql" value="true"/>
  		<property name="hibernate.format_sql" value="true"/>
  		</properties>
	</persistence-unit>
  
</persistence>

 

3.在web环境中手工控制事务。

4.将JPA实现者的jar包添加到运行类路径中，也可以放到tomcat的lib下面。