使用EJBAnnotiation实现持久化到数据库

 1.用NetBeans+Sun Java System Application Server所带的数据库,derby DB,写该项目
    1).建立项目:新建项目->General->java Application
    2).导入需要的jar包:JDK/lib下
          appserv-rt.jar,javaee.jar
          TopLinkEssentials:toplink-essentials.jar,toplink-essentials-agent.jar
          Java DB Driver:derby.jar,derbyclient.jar,derbynet.jar
    3).建立持久单元:新建文件->Persistence->Persistence Unit[选择数据源]
       会生成META-INF/persistence.xml,内容如下

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" 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">
  <persistence-unit name="JavaApplication3PU" transaction-type="RESOURCE_LOCAL">
    <provider>oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider</provider>
    <class>day6.entity.Account</class>
    <properties>
      <property name="toplink.jdbc.url" value="jdbc:derby://localhost:1527/sample"/>
      <property name="toplink.jdbc.user" value="app"/>
      <property name="toplink.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
      <property name="toplink.jdbc.password" value="app"/>
      <property name="toplink.ddl-generation" value="drop-and-create-tables"/>
    </properties>
  </persistence-unit>
</persistence>

    4).建立实体:新建文件->Persistence->Entity class

package day6.entity;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class Account implements Serializable ...{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    public Account() ...{
    }

    public String toString() ...{
        return "day6.entity.Account[id=" + getId() + "]";
    }
    public String getName() ...{
        return name;
    }
    public void setName(String name) ...{
        this.name = name;
    }    
}

    5.建立服务层:新建文件:->java classes->java class

package day6.service;
import day6.entity.Account;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
public class Service ...{    
    private static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JavaApplication3PU");    
    public Service() ...{   }    
    public void persist(Account account) ...{
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        try ...{
            em.persist(account);
            em.getTransaction().commit();
        } catch (Exception e) ...{
            e.printStackTrace();
            em.getTransaction().rollback();
        } finally ...{
            em.close();
        }
    }    
}

     6.)新建测试类进行测试:  

package day6.test;
import day6.entity.Account;
import day6.service.Service;
public class AccountTest ...{
    public AccountTest() ...{    }
    public static void main(String[] args) ...{
        Account account=new Account();
        account.setId(1L);
        account.setName("hoolie");
        Service service=new Service();
        service.persist(account);
    }    
}