@OneToMany和@ManyToOne@Formula之间的java双向关系返回null
基本上,我有两个实体
- 保留地
- 房间
Reservation
实体与Room
实体具有一对多关系。类似地,Room
实体与Reservation
实体具有多对一关系。从Reservation
到Room
的关系始终存在。但是从Room
到Reservation
的关系只有在保留状态标记为“签入”时才存在(我正在为此使用枚举序号。ReservationStatus.CHECKED_IN
的序号是1
)
@OneToMany
注释足以显示一对多关系。对于多对一关系,我使用了@ManyToOne
和@Formula
注释。我刚刚开始冬眠。所以我在MySQL控制台上测试了这个公式,然后制作了这个公式
这是我运行的MySQL查询,我得到了结果。 选择*from reservation r left join reservation_rooms s on r.identifier=s.reservation_identifier left join rooms m on s.rooms_identifier=m.identifier,其中r.reservation_status=1,m.identifier=4
在Room
类中将m.identifier = 4
替换为m.identifier = identifier
。上述查询在MySQL控制台中运行良好。但是当我在应用程序中运行它时,它总是返回null
这是Room
类的源代码
@Entity
public class Room {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer identifier;
private Integer propertyIdentifier;
private String number;
@ManyToOne(cascade = CascadeType.ALL)
private RoomType roomType;
@ManyToOne(cascade = CascadeType.ALL)
private Floor floor;
@ManyToOne(cascade = CascadeType.ALL)
private Block block;
// select * from reservation r left join reservation_rooms s on r.identifier = s.reservation_identifier left join room m on s.rooms_identifier = m.identifier where r.reservation_status = 1 and m.identifier = 4
@Formula(value = "select r from reservation r left join reservation_rooms s on r.identifier = s.reservation_identifier left join room m on s.rooms_identifier = m.identifier where m.identifier = identifier and r.reservation_status = 1")
@ManyToOne(cascade = CascadeType.ALL)
private Reservation occupantReservation;
private Integer statusIdentifier;
public Integer getIdentifier() {
return identifier;
}
public void setIdentifier(Integer identifier) {
this.identifier = identifier;
}
public Integer getPropertyIdentifier() {
return propertyIdentifier;
}
public void setPropertyIdentifier(Integer propertyIdentifier) {
this.propertyIdentifier = propertyIdentifier;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public Integer getStatusIdentifier() {
return statusIdentifier;
}
public void setStatusIdentifier(Integer statusIdentifier) {
this.statusIdentifier = statusIdentifier;
}
public RoomType getRoomType() {
return roomType;
}
public void setRoomType(RoomType roomType) {
this.roomType = roomType;
}
public Floor getFloor() {
return floor;
}
public void setFloor(Floor floor) {
this.floor = floor;
}
public Block getBlock() {
return block;
}
public void setBlock(Block block) {
this.block = block;
}
@Override
public boolean equals(Object object) {
boolean result = false;
if (object == this) {
result = true;
}
else if ((object instanceof Room)) {
Room other = (Room) object;
if (other.identifier.equals(identifier)) {
result = true;
}
}
return result;
}
@Override
public int hashCode() {
return identifier;
}
public Reservation getOccupantReservation() {
return occupantReservation;
}
public void setOccupantReservation(Reservation occupantReservation) {
this.occupantReservation = occupantReservation;
}
}
这是Reservation
类的源代码
@Entity
public class Reservation {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer identifier;
@ManyToOne(cascade = CascadeType.ALL)
private Property property;
@ManyToOne(cascade = CascadeType.ALL)
private Guest guest;
@Temporal(TemporalType.DATE)
private Date arrival;
@Temporal(TemporalType.DATE)
private Date departure;
private Integer nights;
private Integer adults;
private Integer children;
@OneToMany(cascade = CascadeType.ALL)
private Set<Room> rooms;
@Enumerated(value = EnumType.ORDINAL)
private ReservationSource source;
private ReservationStatus reservationStatus;
public Integer getIdentifier() {
return identifier;
}
public void setIdentifier(Integer identifier) {
this.identifier = identifier;
}
public Guest getGuest() {
return guest;
}
public void setGuest(Guest guest) {
this.guest = guest;
}
public Date getArrival() {
return arrival;
}
public void setArrival(Date arrival) {
this.arrival = arrival;
}
public Date getDeparture() {
return departure;
}
public void setDeparture(Date departure) {
this.departure = departure;
}
public Integer getNights() {
return nights;
}
public void setNights(Integer nights) {
this.nights = nights;
}
public Integer getAdults() {
return adults;
}
public void setAdults(Integer adults) {
this.adults = adults;
}
public Integer getChildren() {
return children;
}
public void setChildren(Integer children) {
this.children = children;
}
public Property getProperty() {
return property;
}
public void setProperty(Property property) {
this.property = property;
}
public ReservationStatus getReservationStatus() {
return reservationStatus;
}
public void setReservationStatus(ReservationStatus reservationStatus) {
this.reservationStatus = reservationStatus;
}
public void setRooms(Set<Room> rooms) {
this.rooms = rooms;
}
public Set<Room> getRooms() {
return rooms;
}
public ReservationSource getSource() {
return source;
}
public void setSource(ReservationSource source) {
this.source = source;
}
}
这是MySQL控制台的日志
mysql> describe room;
+---------------------------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------------+--------------+------+-----+---------+-------+
| identifier | int(11) | NO | PRI | NULL | |
| number | varchar(255) | YES | | NULL | |
| property_identifier | int(11) | YES | | NULL | |
| status_identifier | int(11) | YES | | NULL | |
| block_identifier | int(11) | YES | MUL | NULL | |
| floor_identifier | int(11) | YES | MUL | NULL | |
| occupant_reservation_identifier | int(11) | YES | MUL | NULL | |
| room_type_identifier | int(11) | YES | MUL | NULL | |
+---------------------------------+--------------+------+-----+---------+-------+
8 rows in set (0.03 sec)
mysql> describe reservation_rooms;
+------------------------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------------------+---------+------+-----+---------+-------+
| reservation_identifier | int(11) | NO | PRI | NULL | |
| rooms_identifier | int(11) | NO | PRI | NULL | |
+------------------------+---------+------+-----+---------+-------+
2 rows in set (0.01 sec)
mysql> describe reservation;
+---------------------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------------+---------+------+-----+---------+-------+
| identifier | int(11) | NO | PRI | NULL | |
| adults | int(11) | YES | | NULL | |
| arrival | date | YES | | NULL | |
| children | int(11) | YES | | NULL | |
| departure | date | YES | | NULL | |
| nights | int(11) | YES | | NULL | |
| reservation_status | int(11) | YES | | NULL | |
| source | int(11) | YES | | NULL | |
| guest_identifier | int(11) | YES | MUL | NULL | |
| property_identifier | int(11) | YES | MUL | NULL | |
+---------------------+---------+------+-----+---------+-------+
10 rows in set (0.02 sec)
mysql> select * from reservation_rooms;
+------------------------+------------------+
| reservation_identifier | rooms_identifier |
+------------------------+------------------+
| 6 | 4 |
+------------------------+------------------+
1 row in set (0.00 sec)
mysql> select * from reservation;
+------------+--------+------------+----------+------------+--------+--------------------+--------+------------------+---------------------+
| identifier | adults | arrival | children | departure | nights | reservation_status | source | guest_identifier | property_identifier |
+------------+--------+------------+----------+------------+--------+--------------------+--------+------------------+---------------------+
| 6 | 2 | 2018-12-27 | 2 | 2018-12-27 | 2 | 1 | NULL | 5 | NULL |
+------------+--------+------------+----------+------------+--------+--------------------+--------+------------------+---------------------+
1 row in set (0.02 sec)
mysql> select * from rooms;
ERROR 1146 (42S02): Table 'onecube_pms.rooms' doesn't exist
mysql> select * from room;
+------------+--------+---------------------+-------------------+------------------+------------------+---------------------------------+----------------------+
| identifier | number | property_identifier | status_identifier | block_identifier | floor_identifier | occupant_reservation_identifier | room_type_identifier |
+------------+--------+---------------------+-------------------+------------------+------------------+---------------------------------+----------------------+
| 4 | 190 | 1 | 2 | 1 | 2 | NULL | 3 |
+------------+--------+---------------------+-------------------+------------------+------------------+---------------------------------+----------------------+
1 row in set (0.00 sec)
你能告诉我我做错了什么吗?谢谢你抽出时间
# 1 楼答案
我认为使用过滤器更适合您的情况:
1)在^{上定义过滤器:
2)然后在^{上:
3)查询前启用: