我正在实现一个基于两个实体的搜索。

@Entity(name = "user")
public class UserEntity {
    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(updatable = false, nullable = false)
    private String id;
    @Column(unique = true, nullable = false)
    private String email;
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "foo_id", referencedColumnName = "id")
    private FooEntity foo;
    private UserType type;
}
@Entity(name = "foo")
public class FooEntity {
    @Id
    @GeneratedValue(generator="system-uuid")
    @GenericGenerator(name="system-uuid", strategy = "uuid")
    @Column(updatable = false, nullable = false)
    private String id;
    private String identifier;
}

现在，我想根据email adres查找用户，或者根据关系中的标识符查找footentity关系是否存在。并基于userentity中的枚举类型。
我尝试了以下查询：

public static Specification<UserEntity> emailLike(String text) {
     return (root, query, criteriaBuilder) -> criteriaBuilder.like(root.get("email"), "%" + text + "%");
    }
public static Specification<UserEntity> patientIdentifier(String text) {
      return (root, query, criteriaBuilder) -> criteriaBuilder.like(root.join("foo").get("identifier"), "%" + text + "%");
    }
public static Specification<UserEntity> userType(UserType type) {
            return (root, query, criteriaBuilder) -> criteriaBuilder.equal(root.get("type"), type);
        }
final Specification<UserEntity> specification = Specification.where(
                UserSpecification.patientIdentifier(text)
                        .or(UserSpecification.emailLike(text))
        ).and(
                UserSpecification.userType(type)
        );
final Page<UserEntity> userEntities = userRepository.findAll(specification, pageable);

现在，当与footentity的关系存在时，这个查询似乎可以工作。当此关系为null时，即使电子邮件和类型匹配，也不会返回任何内容。
有人能帮我吗？