JPA没有为多对多关系创建数据库条目

Question

我有这两个类(简称(：

@Entity
public class ClanPlayer {
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Id
private int id;
@ManyToMany(mappedBy = "players")
private List<PhoenixPermission> permissions = new ArrayList<>();
public ClanPlayer() {}
public List<PhoenixPermission> getPermissions() {
return permissions;
}
public void setPermissions(List<PhoenixPermission> permissions) {
this.permissions = permissions;
}
public void addPermission(PhoenixPermission permission) {
EntityManager em = EMUtils.getEntityManager();
em.getTransaction().begin();
permissions.add(permission);
em.getTransaction().commit();
}
}

和

@Entity
public class PhoenixPermission {
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Id
private int id;
@ManyToMany
@JoinTable(name = "PLAYER_PERMISSION")
private List<ClanPlayer> players = new ArrayList<>();
public PhoenixPermission() {}
public List<ClanPlayer> getPlayers() {
return players;
}
public void setPlayers(List<ClanPlayer> players) {
this.players = players;
}
}

现在，在使用PhoenixPermission Entity对象调用addPermission方法时，ArrayList"permissions"会更新，但"PLAYER_PERMISSION"表的数据库中没有新的元组。

调试日志没有显示此表的任何插入查询。所有其他实体管理器操作运行良好。我认为我的注释有问题，但我不确定。有什么想法吗？

Answer 1

找到它了。我只需要更新这两个对象。以下是更新的addPermission方法：

public void addPermission(PhoenixPermission permission) {
EntityManager em = EMUtils.getEntityManager();
em.getTransaction().begin();
permissions.add(permission);
permission.getPlayers().add(this);
em.getTransaction().commit();
}