Jpa 涉及继承时很难做到。您是否尝试过其他BatchFetchType选项，例如IN或EXISTS？ @Entity public class Account { @OneToOne private Contact contact; } @En

涉及继承时很难做到。您是否尝试过其他BatchFetchType选项，例如IN或EXISTS？

@Entity
public class Account
{
    @OneToOne
    private Contact contact;
}

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public abstract class Contact {}

@Entity
public class Person extends Contact
{
    @OneToMany
    private List<Hobby> hobbies;
}

@Entity
public class Company extends Contact {}

1 SELECT id, contact_id FROM account
2 SELECT DISTINCT DTYPE FROM contact WHERE (ID = ?)
3 SELECT t0.ID, t0.DTYPE, t1.ID, t1.FOUNDED FROM contact t0, company t1 WHERE ((t0.ID = ?) AND ((t1.ID = t0.ID) AND t0.DTYPE = ?))
4 SELECT DISTINCT DTYPE FROM contact WHERE (ID = ?)
5 SELECT t0.ID, t0.DTYPE, t1.ID, t1.NAME FROM contact t0, person t1 WHERE ((t0.ID = ?) AND ((t1.ID = t0.ID) AND (t0.DTYPE = ?)))
6 SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
... (repetition of lines 2 to 6)

SELECT t3.ID, t3.contact_id, t0.ID, t0.DTYPE, t1.NAME, t2.ID, t2.FOUNDED FROM contacts t0 LEFT OUTER JOIN person t1 ON (t1.ID = t0.ID) LEFT OUTER JOIN company t2 ON (t2.ID = t0.ID), account t3 WHERE (t0.ID = t3.contact_id)
SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
SELECT ID, OUTDOOR, PERSON_ID FROM hobby WHERE (PERSON_ID = ?)
...