我剛開始使用Hibernate,我試圖將兩個座標之間的步行距離映射到HashMap中,可以有多個從「FromCoordinate」到另一個「ToCoordinate」的連接。我不知道我是否已經正確實施了這些,我需要哪些註釋來映射這個MashMap?謝謝使用註解映射Hibernate中的座標HashMap
HashMap> coordWalkingConnections = new HashMap>();
@Entity
@Table(name = "COORDCONNECTIONS")
public class CoordinateConnection implements Serializable{
private static final long serialVersionUID = -1624745319005591573L;
/** auto increasing id number */
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID")
@id
private int id;
@Embedded
public FromCoordinate fromCoord;
@Embedded
public ToCoordinate toCoord;
HashMap<FromCoordinate, ArrayList<ToCoordinate >> coordWalkingConnections = new HashMap<FromCoordinate, ArrayList<ToCoordinate >>();
}
public class FromCoordinate implements ICoordinate
{
@Column(name = "FROM_LAT")
private double latitude;
@Column(name = "FROM_LNG")
private double longitude;
}
public class ToCoordinate implements ICoordinate
{
@Column(name = "TO_LAT")
private double latitude;
@Column(name = "TO_LNG")
private double longitude;
@Column(name = "DISTANCE")
private double distance;
}
DATABASE STRUCTURE
id FROM_LAT FROM_LNG TO_LAT TO_LNG Dist
1 43.352669 -6.264341 43.350012 -6.260653 0.38
2 43.352669 -6.264341 43.352669 -6.264341 0.00
3 46.352669 -6.264341 43.353373 -6.262013 0.17
4 47.352465 -6.265865 43.351290 -6.261200 0.25
5 45.452578 -6.265768 43.352788 -6.264396 0.01
6 45.452578 -6.265768 45.782788 -6.234523 0.01
.....
...
.
Example HashMap for HashMap<Coordinate, ArrayList<Coordinate>>
<KEY{43.352669 -6.264341}, Arraylist VALUES{(43.350012,-6.260653,0.383657), (43.352669, -6.264341, 0.000095), (43.353373, -6.262013, 0.173201)}>
<KEY{47.352465 -6.265865}, Arraylist VALUES{(43.351290,-6.261200,0.258781)}>
<KEY{45.452578 -6.265768}, Arraylist VALUES{(43.352788,-6.264396,0.013726),(45.782788,-6.234523,0.017726)}>
我不確定Hibernate是否可以將列映射到像這樣的列列表。如果這是一個更簡單的列到列映射,您可以使用@CollectionOfElements,@JoinTable和@MapKey。 – 2010-04-16 03:38:05