Hibernate component mapping

A Component is a containted object that is be persisted value type and not an entity.But you can embed the component to entity.

Now We need one-to-one association for husband an wife. We just let the in one table. Then we create one entity, on component.

such as this:

Entity Husband:

 1 @Entity

 2 public class Husband {

 3     private int id;

 4     private String name;

 5     private Wife wife;

 6     @Id

 7     @GeneratedValue

 8     public int getId() {

 9         return id;

10     }

11     public void setId(int id) {

12         this.id = id;

13     }

14     public String getName() {

15         return name;

16     }

17     public void setName(String name) {

18         this.name = name;

19     }

20     @Embedded

21     public Wife getWife() {

22         return wife;

23     }

24     public void setWife(Wife wife) {

25         this.wife = wife;

26     }

27 }

Component Wife:

 1 public class Wife {

 2     private String wifeName;

 3     private int wifeAge;

 4     public String getWifeName() {

 5         return wifeName;

 6     }

 7     public void setWifeName(String wifeName) {

 8         this.wifeName = wifeName;

 9     }

10     public int getWifeAge() {

11         return wifeAge;

12     }

13     public void setWifeAge(int wifeAge) {

14         this.wifeAge = wifeAge;

15     }

16 }

 

We embed the component wife in entity Husband by @Embedded, So we get only one table named Hunband:

1     create table Husband (

2         id integer not null auto_increment,

3         name varchar(255),

4         wifeAge integer not null,

5         wifeName varchar(255),

6         primary key (id)

7     )

 

So, Use component can make our program structual more clear in logic.