Hibernate 一对一主键关联实例

有两个表，product (id ,name)
                    image(id,name)

其中image的主键id引用product的主键id,建立约束，形成1对1

下面的代码，将实现如下功能

（1）新建image对象，新建product对象，通过保存product对象，自动对image对象进行保存，并维护完成性约束

 

CREATE TABLE `product` (
  `id` varchar(50) NOT NULL,
  `name` varchar(50) default NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312;

 

CREATE TABLE `image` (
  `id` varchar(50) NOT NULL,
  `name` varchar(50) default NULL,
  PRIMARY KEY  (`id`),
  CONSTRAINT `image_ibfk_1` FOREIGN KEY (`id`) REFERENCES `product` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312;

 

 

Image和Product的持久类，各持有对方的一个对象，形成1对1关系

 

package onetoone;

public class Image ...{
   private String id;
   private String name;
   private Product product;

public Product getProduct() ...{
    return product;
}
public void setProduct(Product product) ...{
    this.product = product;
}
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 static void main(String[] args) ...{
        Configuration cfg=new Configuration();
        cfg.configure();
        SessionFactory sf=cfg.buildSessionFactory();
        Session session=sf.openSession();
        Transaction t=session.beginTransaction();
        
        Image image=new Image();
        image.setName("image1");
        
        Product product=new Product();
        product.setName("product1");
        product.setImage(image);
        
        session.save(product);
          t.commit();

        System.out.println("success");

    }

 

持久类的mapping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="onetoone"> 
  <class name="Product" table="product"> 
    <id name="id">
      <column name="id"></column>
      <generator class="uuid.hex"></generator>
    </id>
    <property name="name" column="name"></property>
    <one-to-one name="image"
                class="Image"
                cascade="all"
                outer-join="true">
    </one-to-one>
  </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="onetoone"> 
  <class name="Image" table="image"> 
    <id name="id">
      <generator class="foreign">
        <param name="property">product</param>
      </generator>

    </id>
    <property name="name" column="name"></property>
     <one-to-one name="product"
                 class="Product"
                 cascade="all"
                 outer-join="true">
    </one-to-one>
  </class> 

</hibernate-mapping>

 

测试代码

其中product.setImage(image);
        image.setProduct(product); 很关键，如果写product,setImage(image)会报异常

    public static void main(String[] args) ...{
        Configuration cfg=new Configuration();
        cfg.configure();
        SessionFactory sf=cfg.buildSessionFactory();
        Session session=sf.openSession();
        Transaction t=session.beginTransaction();
        
        Image image=new Image();
        image.setName("image1");
        
        Product product=new Product();
        product.setName("product1");
        product.setImage(image);
        image.setProduct(product);
        session.save(product);
        
        t.commit();
        Product product1=(Product)session.get(Product.class, "40288018114a1c4e01114a1c507e0001");
        System.out.println(product1);
        System.out.println(product1.getImage());
        

        System.out.println("success");

    }