hibernate的自定义主键

最新推荐文章于 2023-04-06 19:13:24 发布

ch469299503

最新推荐文章于 2023-04-06 19:13:24 发布

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分类专栏： hibernate 文章标签： hibernate string session date class import

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本文介绍了一个基于Java的项目中如何使用Hibernate框架来实现自定义主键生成策略。具体包括定义实体类MyOrder、配置映射文件MyOrder.hbm.xml及HQL.hbm.xml，并实现一个自定义主键生成器OrderIdentifier。最后通过测试类演示了保存带有自动生成ID的订单。

//pojos

import java.io.Serializable;

public class MyOrder implements Serializable {

/**
*
*/
private static final long serialVersionUID = 1L;
private String id;
private String name;
private String password;
public String getId() {
  return id;
}
public void setId(String id) {
  this.id = id;
}
public String getName() {
  return name;
}
public void setName(String name) {
  this.name = name;
}
public String getPassword() {
  return password;
}
public void setPassword(String password) {
  this.password = password;
}

}

//MyOrder.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
package="cn.itcast.pojos">
  <class name="MyOrder" table="myOrder">
   <id name="id" column="id">
    <generator class="cn.itcast.identifier.OrderIdentifier"></generator>
   </id>
   <property name="name" column="name"></property>
   <property name="password" column="password"></property>
  </class>

</hibernate-mapping>

//HQL.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
package="cn.itcast.pojos">
  <query name="myOrder.id">
   select max(id) from MyOrder where id like ?
  </query>

</hibernate-mapping>

//自定义主键要实现的接口

import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.IdentifierGenerator;

public class OrderIdentifier implements IdentifierGenerator {

public Serializable generate(SessionImplementor session, Object arg1)
   throws HibernateException {
  Date date = new Date();
  SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
  String today = format.format(date);
  Query query = session.getNamedQuery("myOrder.id");
  query.setParameter(0, "RK" + today + '%');
  List<String> list = query.list();
  String id = list.get(0);
  if(id != null)
  {
   return "RK" + (Long.parseLong(id.substring(2)) + 1);
  }else
  {
   return "RK" + today + "0001";
  }
}

}

//这是测试类

import org.hibernate.Session;
import org.hibernate.Transaction;

import cn.itcast.pojos.MyOrder;
import cn.itcast.util.HibernateSessionFactory;

public class Test {

public static void main(String[] args) {

  Session session = HibernateSessionFactory.getSession();
  Transaction transaction = session.beginTransaction();
  MyOrder order = new MyOrder();
  order.setName("张三");
  order.setPassword("11111");
  session.save(order);
  transaction.commit();
  session.close();
}
}