Question

环境：

Hibernate 4.1.6.final
Spring 3.1.2.release
Spring JPA 1.1.0.release
PostgreSQL 9.1-901-1.jdbc4

我决定重新解释这些问题。

有2个表：

public company
{
  private Long id;
  private Long name;
  private address table_address;
}
public address
{
  private Long id;
  private String address;
  private Long company_id;
}

注意：两个表id都是顺序的，没有相关性。 table.address.company_id除外是公司的外键。

如何做映射？我期望的结果是：

"company":{
            "id":4,
            "name":"company name",
            "address":{
                         "id":3,
                         "address":"anywhere",
                         "company_id":4
                      }
          }

有人可以教我这个，如何映射这2张表吗？

Answer 1

您想要的是Company和Address

之间的一对一映射

只需将@OneToOne注释添加到公司类的table_address字段：

 public class Address {

        @Id
        @GeneratedValue
        private Long id;
        private String address;
        @OneToOne
        @PrimaryKeyJoinColumn
        private Company company;

        //getters and setters
    }

public class Company {

    @Id
    @GeneratedValue
    private Long id;
    private String name;
    @OneToOne(mappedBy = "company",cascade = CascadeType.ALL)
    private Address companyAddress;

    //getters and setters
}

<子> 除了问题：尊重java命名约定，在你的情况下，类名应该以大写字母开头，也应该以变量名中的下一个字开头。即公司应公司且地址应地址，private address table_address;更改为private Address companyAddress; }

更新了解决方案

public class Address {

    @Id
    @GeneratedValue
    private Long id;
    private String address;
    @OneToOne
    @JoinColumn(name = "company_id")
    private Company company;

    //getters and setters
}

public class Company {

    @Id
    @GeneratedValue
    private Long id;
    private String name;
    @OneToOne(mappedBy = "company",cascade = CascadeType.ALL)
    private Address companyAddress;

    //getters and setters
}

来自stupidfrog：如果你使用@PrimaryKeyJoinColumn，则id加入错误。 id连接主要但不是地址表company_id

这是来自hibernate的引用 http://docs.jboss.org/hibernate/jpa/2.1/api/javax/persistence/OneToOne.html 例1

Answer 2

您应该创建两个实体类，如下所示

公司实体

    @Entity
    @Table(name = "YOUR TABLE NAME")
    public company{

       @Id
       @GeneratedValue(strategy = GenerationType.IDENTITY)
       @Basic(optional = false)
       @Column(name = "COMPANY_ID")
       private Long id;
       @Column(name = "NAME")
       private Long name;
       @JoinColumn(name = "ADDRESS_ID")
       @OneToOne(optional = false)
       private address table_address;
    }

ADDRESS ENTITY

   @Entity
   @Table(name = "YOUR TABLE NAME")
   public address{

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    private Long id;
    @Column(name = "ADDRESS")
    private String address;
    @JoinColumn(name = "COMPANY_ID")
    @OneToOne(optional = false)
    private Long company_id;
}

希望这有帮助

JPA，Hibernate：仅使用外键的OneToOne映射

2 个答案: