休眠用戶和朋友關係添加其他列

Question

我想通過休眠來創建好友系統，並且我需要檢查此用戶與其他用戶關聯的時間。

我希望像下面的代碼表中的列：

table 1: 
    int id; 
    String name; 

table 2: 
    int user_id; 
    int friend_id; 
    Date startdate; 

POJO代碼：

public class User { 
    private int id; 
    private String name; 
    private Map<User,Date> friends; 
} 

Answer 1

我認爲你需要罷了然後JPA。就像這樣：

@Entity 
@Table(name = "users") 
public class User implements Serializable { 

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

    @Column 
    private String name; 

    @ElementCollection(fetch = FetchType.EAGER) 
    @CollectionTable(name = "friendship", joinColumns = @JoinColumn(name = "user_id")) 
    @MapKeyColumn(name = "friend_id") 
    @Column(name = "start_date") 
    private Map<Long, Date> friendshipMap; 

    ... getters/setters ... 

}