我將如何使用jpa在jpa對象列表中查詢參數

Question

不幸的是，我不知道該如何表達這個問題。

我有兩個只是松散相關的表，PERSON和ASSIGNMENT。

public class Person {

    @EmbeddedId
    @Column
    PersonPK id;

    @Column
    String otherStuff;
}

public class PersonPK {

    @Column
    long personNumber;

    @Column
    Date hireDate;

    @Column
    Date terminationDate;
}

public class Assignment {
    @Id
    @Column
    long id;

    @Column
    long personId;

    @Column
    boolean active;

    @Column
    String otherStuff;
}

可以很容易地FROM Person p WHERE [current date in between hire and termination]那里找到一個FROM Person p WHERE [current date in between hire and termination]

但是我需要對分配進行第二次查詢，我只想將“人員”列表傳遞回去，而不是剝離ID。 所以類似FROM Assignment a WHERE a.personId IN :persons.id.id AND a.active = true

JPA查詢可能嗎？

Answer 1

帶有這樣的日期字段的@EmbeddedId似乎@EmbeddedId 。 老實說，我會丟失PersonPK類，並執行以下操作：

public class Person {
    @Id
    @Column
    long personNumber;

    @Column
    Date hireDate;

    @Column
    Date terminationDate;

    @Column
    String otherStuff;
}

public class Assignment {
    @Id
    @Column
    long id;

    @ManyToOne
    Person person;

    @Column
    boolean active;

    @Column
    String otherStuff;
}

然后，您應該可以通過傳遞人員列表進行查詢：

List<Person> people = /* your list of people */
Query query = manager.createQuery("select a from Assignment a where a.person in :people");
query.setParameter("people", people);
List<Assigment> assignments = query.getResultList()

之所以@ManyToOne ，是因為您實際上是使用@ManyToOne注釋在Person類和Assignment類之間建立鏈接。

編輯：看來您無法更改架構，我只是向person添加一個靜態助手來為您獲取personNumbers：

public static List<Long> toPersonNumbers(List<Person> people) {
    List<Long> numbers = new ArrayList<Long>();
    for ( Person person: people ) {
        numbers.add(person.id.personNumber);
    }
    return numbers;
}

然后可以在需要設置參數時調用它：

List<Person> people = /* your list of people */
Query query = manager.createQuery("select a from Assignment a where a.personId in :people");
query.setParameter("people", toPersonNumbers(people));
List<Assigment> assignments = query.getResultList()