接上）



具体过程如下：

(1)首先建立数据库配置文件，我们在这里定为database.xml,当然也可以改成是其它名字。

<?xml version="1.0" encoding="gb2312"?>

<database name="CustomerDemo" engine="mysql">

<driver url="jdbc:mysql://cwb:3306/quickstart" class-name="org.gjt.mm.mysql.Driver">

<param name="user" value="dbusername"/>

<param name="password" value="dbpassword "/>

</driver>

<mapping href="Customer.xml"/>

</database>




建立影射文件Customer.xml

<?xml version="1.0" encoding="gb2312"?>

<class name="Demo.Customer" access="shared" identity="customerID">

<map-to table="users"/>

<field name="customerID" type="integer">

<sql name="customerID" type="integer"/>

</field>

<field name="name" type="string">

<sql name="name" type="varchar"/>

</field>

</class>




建立持久化类，与hibernate的是一样的类似javabean的类

package Demo;

public class Customer {

private String name;

private int customerID;

public Customer() {

}



public int getCustomerID() {

return customerID;

}



public void setCustomerID(int customerID) {

this.customerID = customerID;

}



public String getName() {

return name;

}



public void setName(String name) {

this.name = name;

}

}




基本的实现后，我们可以看看这个demo怎么运行。

import java.util.*;

import org.exolab.castor.jdo.*;

import java.net.*;



public class CustomerManager {

JDO jdo;

Database db;

public CustomerManager() throws DatabaseNotFoundException,

PersistenceException {



//定义一个JDO对象

jdo = new JDO();

jdo.setDatabaseName("CustomerDemo");

jdo.setConfiguration("database.xml");

jdo.setClassLoader(getClass().getClassLoader());



//获得连接数据库

db = jdo.getDatabase();

}

/**

* 用于读取用户

* @param id Customer 对象的主键

*/

public Customer loadCustomer(Integer id) throws DatabaseNotFoundException,

PersistenceException {



Customer result = null;



//开始事务

db.begin();

result = (Customer) db.load(Customer.class, id);



//完成事务，关闭数据库

db.commit();

db.close();

return result;

}



/**

* 用于建立用户

* @param Customer newCustomer 新对象

*/

public void createCustomer(Customer newCustomer) throws

DatabaseNotFoundException,

PersistenceException {


Customer result = null;

db.begin();



//新建Customer

db.create(newCustomer);



db.commit();

db.close();

}



/**

* 更新旧的对象

*/

public Customer updateCustomer(Customer updateCustomer) throws

DatabaseNotFoundException,

PersistenceException {



db.begin();