如何访问@EmbeddedId的字段? [英] How to access fields of @EmbeddedId?

问题描述

我有一个具有复合主键的@Entity.因此，我创建了一个包含PK字段的@EmbeddedId.

I have an @Entity that has a composite primary key. Therefore I created an @EmbeddedId holding the PK fields.

问题:直接通过id.*访问这些字段是否更好，还是应该在父类中创建getter/setter?

Question: is it better to access those fields by id.* directly, or should I create getter/setter in the parent class?

示例:

@Entity
public class MyPerson {
    @EmbeddedId
    private PersonId id;

    public String getFirstname() {
        return id.getFirstname();   
    }

    public String getLastname() {
        return id.getLastname();
    }

    public LocalDate getDob() {
        return id.getDob();
    }   
}

@Embeddable
public class PersonId implements Serializable {
    private String firstname;
    private String lastname;
    private LocalDate dob;

    //getter+setter as well
}

我最好使用person.getFistname()还是person.getId().getFirstname()?

前者更为清晰，但缺点是我必须在MyPerson和PersonId中都创建吸气剂.

The former is more clear, but with the drawback that I'd have to create the getters both in MyPerson and in PersonId.

首选的访问方式是什么，为什么?

What should be the preferred way to access, and why?

推荐答案

您不必创建属性

private PersonId id

替代项是

@Entity  @IdClass(PersonId.class)
public class MyPerson {
    @Id private String firstname;
    @Id private String lastname;
    @Id private LocalDate dob;

    // Getters and setters here    
}

并仅将PersonId用于加载 MyPerson 实体:

And use PersonId only for loading MyPerson entities:

PersonId peronId = new PersonId(firstname, lastname, dob);
MyPerson person = session.get(MyPerson.class, personId);

这篇关于如何访问@EmbeddedId的字段?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！