Hibernate:获取集合
我在尝试获取元素集合时遇到了一个问题:Friend集合为空 共有3类:Hibernate:获取集合,hibernate,Hibernate,我在尝试获取元素集合时遇到了一个问题:Friend集合为空 共有3类: @Entity @Table(name="USER") public class User { @Id @Column(name="USER_ID", nullable=false) private String mail; @Column(name="PASSWORD") private String password; @Column(name="SURNAME") private String surname;
@Entity
@Table(name="USER")
public class User {
@Id
@Column(name="USER_ID", nullable=false)
private String mail;
@Column(name="PASSWORD")
private String password;
@Column(name="SURNAME")
private String surname;
@Column(name="NAME")
private String name = null;
@Column(name="STATUT")
private StatutUser statut;
@Column(name="PHONENUMBER")
private int phoneNumber;
@OneToMany(cascade = CascadeType.PERSIST, mappedBy="friendPK.friend")
@Fetch(FetchMode.JOIN)
private Set<Friend> friends = new HashSet<Friend>();
...
Some getters and setters
最后一点:
@SuppressWarnings("serial")
@Embeddable
public class FriendPK implements Serializable{
@ManyToOne
@JoinColumn(name="USER1_ID", referencedColumnName="USER_ID")
protected User user1;
@ManyToOne
@JoinColumn(name="USER2_ID", referencedColumnName="USER_ID")
protected User friend;
}
当我尝试获取所有好友的用户时,集合为空
以下是添加关系的方法的文件:
private EntityManagerFactory emf;
private EntityManager manager;
public String addFriends(String mail1, String mail2){
EntityTransaction t;
t = manager.getTransaction();
try{
t.begin();
User user = manager.find(User.class, mail1);
User friend = manager.find(User.class, mail2);
Friend f = new Friend();
f.setStatutFriend(StatutFriend.TOCHECK);
FriendPK friendPK = new FriendPK();
friendPK.setFriend(friend);
friendPK.setUser1(user);
f.setFriendPK(friendPK);
Set<Friend> relationship = new HashSet<Friend>();
relationship = user.getFriends();
relationship.add(f);
Set<Friend> relationship2 = new HashSet<Friend>();
relationship2 = friend.getFriends();
relationship2.add(f);
user.setFriends(relationship);
friend.setFriends(relationship2);
manager.persist(user);
t.commit();
error.setReq(StatutReq.DONE);
}
catch(Exception e){
error.setReq(StatutReq.ABORTED);
error.setError(e.getMessage());
}
finally
{
if (t.isActive())
{
t.rollback();
}
}
私有实体管理器工厂emf;
私人实体经理;
公共字符串addFriends(字符串mail1、字符串mail2){
实体交易t;
t=manager.getTransaction();
试一试{
t、 begin();
User=manager.find(User.class,mail1);
User-friend=manager.find(User.class,mail2);
Friend f=新朋友();
f、 设置StatutFriend(StatutFriend.TOCHECK);
FriendPK FriendPK=新的FriendPK();
friendPK.setFriend(friend);
friendPK.setUser1(用户);
f、 setFriendPK(friendPK);
Set relationship=newhashset();
relationship=user.getFriends();
关系。添加(f);
Set relationship2=新的HashSet();
relationship2=friend.getFriends();
关系2.添加(f);
user.setFriends(关系);
friend.setFriends(关系2);
manager.persist(用户);
t、 提交();
setReq错误(statureq.DONE);
}
捕获(例外e){
setReq错误(statureq.中止);
error.setError(例如getMessage());
}
最后
{
if(t.isActive())
{
t、 回滚();
}
}
请原谅我的代码…我是初学者!
非常感谢。乍一看,尽管您的体系结构看起来很奇怪,但代码似乎是正确的。 friendFK代表什么? 用户不需要持有一组用户集吗? 从数据库的角度来看,关系表是必要的,但在java模型中不是 如果我是你,我会删除这个类并使用hbm2dll工具生成正确的匹配数据库模式
请指定您的Hibernate和jars版本,并将您的Hibernate配置文件提供给我们以进行检查。谢谢您的回答。我在没有使用friendFK的情况下更改了全局结构。现在它可以工作了!
private EntityManagerFactory emf;
private EntityManager manager;
public String addFriends(String mail1, String mail2){
EntityTransaction t;
t = manager.getTransaction();
try{
t.begin();
User user = manager.find(User.class, mail1);
User friend = manager.find(User.class, mail2);
Friend f = new Friend();
f.setStatutFriend(StatutFriend.TOCHECK);
FriendPK friendPK = new FriendPK();
friendPK.setFriend(friend);
friendPK.setUser1(user);
f.setFriendPK(friendPK);
Set<Friend> relationship = new HashSet<Friend>();
relationship = user.getFriends();
relationship.add(f);
Set<Friend> relationship2 = new HashSet<Friend>();
relationship2 = friend.getFriends();
relationship2.add(f);
user.setFriends(relationship);
friend.setFriends(relationship2);
manager.persist(user);
t.commit();
error.setReq(StatutReq.DONE);
}
catch(Exception e){
error.setReq(StatutReq.ABORTED);
error.setError(e.getMessage());
}
finally
{
if (t.isActive())
{
t.rollback();
}
}