表person对应的model类：

@Entity
@Table(name = "person")
public class Person {
    @Id
    @GeneratedValue
    private Long id;
    private Integer age;
    private String name;
    @Column(name = "nick_name")
    private String nickName;
    private String company;
    private Date birthday;
    @OneToMany(cascade = ALL)
    private Set<Phone> phones = new HashSet<>();
      // getter and setter}

表phone对应的model类：

@Entity
@Table(name = "phone")
public class Phone {
    @Id
    @GeneratedValue
    private Long id;

    private String number;
    private String brand;
    @ManyToOne
    private Person person;
    // getter and setter}

数据库访问PhoneRepository类：

public interface PhoneRepository extends JpaRepository<Phone, Long>, JpaSpecificationExecutor<Phone> {
}

查询姓名为"Jack"，用的手机为"HuaWei"的人。

public List<Phone> findAll(SearchRequest request) {
    Specification<Phone> specification = new Specifications<Phone>()
        .eq(StringUtils.isNotBlank(request.getBrand()), "brand", "HuaWei")
        .eq(StringUtils.isNotBlank(request.getPersonName()), "person.name", "Jack")
        .build();

    return phoneRepository.findAll(specification);
}