Spring JPA 使用规范与关联表的连接

问题描述

我有这个实体：

public class DeskRoom {

    @Id
    private Long id;
    private String name;
}

public class DeskRoomEquipment {

    @Id
    private Long id;

    @ManyToOne
    @JoinColumn(name = "desk_room_id")
    private DeskRoom deskRoom;

    @ManyToOne
    @JoinColumn(name = "equipment_id")
    private Equipment equipment;
}

public class Equipment {
    @Id
    private Long id;
    private String name;
}

我想创建一个规范，通过设备名称列表过滤所有桌面房间。我试过这样的事情，但创建的查询是交叉连接。

public static Specification<DeskRoom> containsEquipment(final List<String> equipmentName) {
        return (root,criteriaQuery,criteriaBuilder) -> {
               final Root<DeskRoomEquipment> deskRoomEquipmentRoot = criteriaQuery.from(DeskRoomEquipment.class);

                return criteriaBuilder.and(criteriaBuilder.equal(root,deskRoomEquipmentRoot.get("deskRoom")),deskRoomEquipmentRoot.get("equipment").get("name").in(equipmentName));
        }
}

创建的查询：

select *
from desk_room deskroom0_
         cross join desk_room_equipment deskroomeq1_
         cross join equipment equipment3_
where deskroomeq1_.equipment_id = equipment3_.id
  and deskroom0_.id = deskroomeq1_.desk_room_id
  and (equipment3_.name in (?))

想要的查询：

select *
from desk_room deskroom0_
          join desk_room_equipment deskroomeq1_ on deskroom0_.id = deskroomeq1_.desk_room_id
          join equipment equipment3_ on deskroomeq1_.equipment_id = equipment3_.id
where  (equipment3_.name in (?))

解决方法

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