Hibernate中抽象化主键使用教程

首先，在数据库中建立表：
CREATE TABLE `container` (
  `containerId` varchar(50) NOT NULL,
  `container_type` varchar(50) NOT NULL,
  `size` double default NULL,
  `name` varchar(50) default NULL,
  `description` varchar(50) default NULL,
  `height` double default NULL,
  `length` double default NULL,
  `width` double default NULL,
  `diameter` double default NULL,
  PRIMARY KEY  (`containerId`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312;

 

其中Container是一个抽象类，其下有两个子类Box和Bottle

 

package abstracttest;

public abstract class Container ...{
  private String containerId;
  private double size;
  private String name;
  private String description;
public String getContainerId() ...{
    return containerId;
}
public void setContainerId(String containerId) ...{
    this.containerId = containerId;
}
public String getDescription() ...{
    return description;
}
public void setDescription(String description) ...{
    this.description = description;
}
public String getName() ...{
    return name;
}
public void setName(String name) ...{
    this.name = name;
}
public double getSize() ...{
    return size;
}
public void setSize(double size) ...{
    this.size = size;
}
}

 

package abstracttest;

public class Bottle extends Container ...{
  private double diameter;
  private double height;
public double getDiameter() ...{
    return diameter;
}
public void setDiameter(double diameter) ...{
    this.diameter = diameter;
}
public double getHeight() ...{
    return height;
}
public void setHeight(double height) ...{
    this.height = height;
}
}

 

package abstracttest;

public class Box extends Container ...{
    private double height;
    private double length;
    private double width;
    public double getHeight() ...{
        return height;
    }
    public void setHeight(double height) ...{
        this.height = height;
    }
    public double getLength() ...{
        return length;
    }
    public void setLength(double length) ...{
        this.length = length;
    }
    public double getWidth() ...{
        return width;
    }
    public void setWidth(double width) ...{
        this.width = width;
    }
}

 

在HBM文件中，定义，抽象类的配置

 

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping package="abstracttest">
    <class name="Container" abstract="true" table="container">
       <id name="containerId">
         <generator class="uuid.hex"></generator>
       </id>
       <discriminator column="container_type"></discriminator>
       <property name="size" column="size"></property>
       <property name="name" column="name"></property>
       <property name="description" column="description"></property>
       <subclass name="Box" discriminator-value="BOX">
         <property name="height" column="height"></property>
         <property name="width" column="width"></property>
         <property name="length" column="length"></property>
       </subclass>
       <subclass name="Bottle" discriminator-value="BOTTLE">
         <property name="diameter" column="diameter"></property>
         <property name="height" column="height"></property>
       </subclass>
    </class>
</hibernate-mapping>

 

最后是测试代码

package abstracttest;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;


public class Test ...{

    /** *//**
     * @param args
     */
    public static void main(String[] args) ...{
        Configuration cfg=new Configuration();
        cfg.configure();
        SessionFactory sf=cfg.buildSessionFactory();
        Session session=sf.openSession();
        Transaction t=session.beginTransaction();
        Box box1=new Box();
        box1.setName("木箱子");
        box1.setHeight(50);
        box1.setLength(50);
        box1.setWidth(50);
        box1.setDescription("包装电视机");
        box1.setSize(12500);
        
        Bottle bottle1=new Bottle();
        bottle1.setName("玻璃瓶子");
        bottle1.setDescription("喝牛奶用");
        bottle1.setSize(139.12);
        bottle1.setDiameter(6);
        bottle1.setHeight(12);
        
        session.save(box1);
        session.save(bottle1);
        t.commit();
        System.out.println("success");
        
    }

}

 

可以看到，数据库的记过如下，

containerId	container_type	size	name	description	height	length	width	diameter
402880181144b2f4011144b2f6f00001	BOX	12500	木箱子	包装电视机	50	50	50	<NULL>
402880181144b2f4011144b2f6ff0002	BOTTLE	139.12	玻璃瓶子	喝牛奶用	12	<NULL>	<NULL>	6

其中container_type的区分字段是我们在hbm文件中的设置