Hibernate继承映射--每个子类一个数据表的实现案例

这种方式，不再针对父类Container有专门的数据表和映射文件，hibernate隐性的通过
Container与两个子类的继承关系实现这一效果

数据库结构：

CREATE   TABLE  `box2` (
  `id`  varchar ( 50 )  NOT   NULL   default   ' 0 ' ,
  `size`  double   default   NULL ,
  `name`  varchar ( 50 )  default   NULL ,
  `description`  varchar ( 50 )  default   NULL ,
  `width`  double   default   NULL ,
  `height`  double   default   NULL ,
  ` len `  double   default   NULL ,
   PRIMARY   KEY   (`id`)
) ENGINE = InnoDB  DEFAULT  CHARSET = gb2312;



CREATE   TABLE  `bottle2` (
  `id`  varchar ( 50 )  NOT   NULL   default   ' 0 ' ,
  `size`  double   default   NULL ,
  `name`  varchar ( 20 )  default   NULL ,
  `diameter`  double   default   NULL ,
  `height`  double   default   NULL ,
  `description`  varchar ( 50 )  default   NULL ,
   PRIMARY   KEY   (`id`)
) ENGINE = InnoDB  DEFAULT  CHARSET = gb2312;

 实体关系：

 

package  extendstesttwo;

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  extendstesttwo;

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;
    }
}


package  extendstesttwo;
// hibernate多态支持的策略，每个子类一张表
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;
}
}

映射文件：

<? 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 ="extendstesttwo" >
     < class  name ="Bottle"  table ="bottle2" >
        < id  name ="containerId"  column ="id" >
          < generator  class ="uuid.hex" ></ generator >
        </ id >
        < property  name ="size"  column ="size" ></ property >
        < property  name ="name"  column ="name" ></ property >
        < property  name ="description"  column ="description" ></ property >
        < property  name ="height"  column ="height" ></ property >
        < property  name ="diameter"  column ="diameter" ></ property >
       </ class >
</ hibernate-mapping >

<? 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 ="extendstesttwo" >
     < class  name ="Box"  table ="box2" >
        < id  name ="containerId"  column ="id" >
          < generator  class ="uuid.hex" ></ generator >
        </ id >
        < property  name ="size"  column ="size" ></ property >
        < property  name ="name"  column ="name" ></ property >
        < property  name ="description"  column ="description" ></ property >
        < property  name ="height"  column ="height" ></ property >
        < property  name ="width"  column ="width" ></ property >
        < property  name ="length"  column ="len" ></ property ><sp>