如何使用 JpaRepository 和嵌套的对象列表进行搜索?

2022-01-18 00:00:00 java spring-boot jpa spring-data

说明

有一个PersonRepository和Person实体，Person 类包含 List.Qualification 类有 3 个简单字段.

There is a PersonRepository and Person entity, Person class contains List<Qualification>. Qualification class has 3 simple fields.

我尝试在自定义方法上添加 @Query 注释并使用 JPQL 获取结果，但 Qualification 类字段在 JPQL 中不可用于操作，因为它是存储库本身包含 List 而不仅仅是 Qualification 的简单字段.

I have tried to add @Query annotation on custom method and use JPQL to get the results, but Qualification class fields were not available for manipulation in JPQL as it repository itself contains List<Qualification> instead of just a simple field of Qualification.

如何通过这些 Qualification 的嵌套字段进行搜索?

How can I search by these Qualification's nested fields?

查询

现在我需要找到资格的 experienceInMonths 大于 3 且小于 9 且资格的名称字段 = 'java' 的人员实体列表.

Now I need to find list of person entity where qualification's experienceInMonths is greater than 3 and less than 9 AND qualification's name field = 'java'.

代码

Person.java

Person.java

@Data
@Entity
public class Person {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private String id;

@NotEmpty
@Size(min = 2)
private String name;

@NotEmpty
@Size(min = 2)
private String surname;

@ElementCollection(targetClass = java.util.ArrayList.class, fetch = FetchType.EAGER)
private List<Qualification> qualifications = new ArrayList<>();

}

PersonRepository.java

PersonRepository.java

@Repository
public interface PersonRepository extends JpaRepository<Person, String> {
}

Qualification.java

Qualification.java

@Data
@AllArgsConstructor
public class Qualification implements Serializable {

    @Id @GeneratedValue
    private String id;
    private String name;
    private String experienceInMonths;
}

不重复 这篇文章，因为这里是嵌套对象的集合.不仅仅是单一参考.

not duplicate of this post, as here is the collection of nested objects. Not just single reference.

推荐答案

首先，将 experienceInMonths 从 String 改为 int (否则你可以不要将字符串与数字进行比较).然后你可以尝试使用这个香肠":

First, change experienceInMonths from String to int (otherwise you can not compare the string with the number). Then you can try to use this 'sausage':

List<Person> findByQualifications_experienceInMonthsGreaterThanAndQualifications_experienceInMonthsLessThanAndName(int experienceGreater, int experienceLess, String name);

或者你可以尝试使用这个相当不错的方法:

Or you can try to use this pretty nice method:

@Query("select p from Person p left join p.qualifications q where q.experienceInMonths > ?1 and q.experienceInMonths < ?2 and q.name = ?3")
List<Person> findByQualification(int experienceGreater, int experienceLess, String name);

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